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IAI CSCSA practice questions

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Question 1Crime Scene Investigation

During the initial walk-through of a homicide scene, the lead CSI should first prioritize which of the following actions?

  1. Establishing a controlled entry path and identifying fragile evidence Correct answer.
  2. Collecting the weapon for immediate laboratory submission
  3. Photographing every item before any assessment
  4. Interviewing all neighbors before entering the scene

Explanation

The initial walk-through is a planning and assessment phase. The CSI establishes a safe, controlled path and notes transient or fragile evidence such as odors, footprints, and blood spatter that may degrade before detailed processing begins.

Question 2Crime Scene Investigation

Which documentation method creates a permanent, contemporaneous account of scene conditions and CSI actions?

  1. Sketch
  2. Chain-of-custody form
  3. Scene notes Correct answer.
  4. Photographic log

Explanation

Scene notes are the running contemporaneous record of observations, times, personnel, and actions taken. They support later testimony and tie together photographs, sketches, and evidence logs.

Question 3Crime Scene Investigation

A CSI photographs a bloodstained shirt on a bed, then photographs the same shirt again after placing a scale beside it. This practice best supports which documentation principle?

  1. Close-up images should be taken only after the item is packaged
  2. Each evidence item requires only one image to reduce redundancy
  3. Photographs should always be taken without a scale to preserve natural appearance
  4. Overall, midrange, and close-up images should be captured before the item is moved Correct answer.

Explanation

Standard photographic protocol captures overall, midrange, and close-up views, with and without a scale, before the item is moved or altered. This preserves both context and detail for later reconstruction.

Question 4Crime Scene Investigation

Which sketch method is most appropriate for recording the location of a body and surrounding furniture in a single room?

  1. Baseline method along an exterior roadway
  2. Triangulation from a single landmark
  3. Polar coordinate method from an arbitrary point
  4. Rectangular coordinate method using two fixed reference walls Correct answer.

Explanation

The rectangular coordinate method measures each item perpendicular to two fixed reference planes, which suits indoor scenes with straight walls. It produces reliable, easily interpreted positions for items and the body.

Question 5Crime Scene Investigation

What is the primary purpose of establishing a single controlled entry point at a crime scene?

  1. To document the number of officers present
  2. To speed up evidence collection by limiting staff
  3. To minimize contamination and preserve the scene's integrity Correct answer.
  4. To satisfy media requests for access

Explanation

A single controlled entry point limits the number of people and paths through the scene, reducing contamination and preserving evidence. It also supports an accurate record of who entered and when.

Question 6Crime Scene Investigation

Which of the following best describes the purpose of a chain-of-custody record?

  1. To list the names of all officers who responded to the call
  2. To summarize the CSI's scene notes for court
  3. To document the investigative theory of the case
  4. To record every transfer, date, and handler of evidence from collection to disposition Correct answer.

Explanation

The chain of custody is a chronological record of who handled evidence, when, and for what purpose. It establishes integrity and admissibility by showing continuous, accountable possession.

Question 7Crime Scene Investigation

Before collecting a firearm at a scene, the CSI should take which action to preserve potential latent prints and trace evidence?

  1. Document the weapon's position and condition, then lift it by textured surfaces Correct answer.
  2. Insert a pen or rod through the barrel to lift it
  3. Clean the weapon with a cloth to remove oils
  4. Handle the weapon by the grip and unload it immediately

Explanation

Firearms are documented in place and lifted by textured areas such as the grip or checkering to avoid disturbing latent prints on smooth surfaces. Unloading is typically left to qualified personnel following agency protocol.

Question 8Crime Scene Investigation

Which scene search pattern is best suited to a large, open outdoor area with few natural boundaries?

  1. Wheel search radiating from a single point
  2. Line or strip search with searchers spaced at arm's length Correct answer.
  3. Zone search limited to a single quadrant
  4. Spiral search from the center outward

Explanation

A line or strip search uses searchers moving in parallel lines across an area, making it effective for large open spaces. The spacing and overlapping passes ensure thorough coverage.

Question 9Crime Scene Investigation

A CSI arrives at a scene where a window has been broken inward and glass fragments are scattered on the floor. Which documentation approach best supports reconstruction?

  1. Sweep the glass into a single pile before photographing
  2. Photograph the glass in place with scale and record the distribution pattern Correct answer.
  3. Discard small fragments as non-evidential debris
  4. Collect only the largest fragments for laboratory analysis

Explanation

Glass distribution patterns can indicate direction of force and point of impact. Photographing in place with scale and recording distribution preserves the pattern for reconstruction.

Question 10Crime Scene Investigation

Which factor most strongly justifies establishing a perimeter larger than the apparent scene?

  1. The number of responding officers
  2. The possibility that evidence or pathways extend beyond the visible scene Correct answer.
  3. The availability of barrier tape
  4. The media's request for a wider cordon

Explanation

Perimeters should encompass all areas that may contain evidence, including approach and escape routes. Erring larger protects evidence that may not be immediately visible.

Question 11Crime Scene Investigation

During collection of a bloodstained item, which practice best preserves both DNA and pattern information?

  1. Fold the stained area against itself to protect it
  2. Sprinkle the item with a preservative powder
  3. Seal the wet item in a plastic bag immediately
  4. Allow the item to air-dry before packaging in paper Correct answer.

Explanation

Biological evidence should be air-dried before packaging in breathable containers to prevent degradation and mold growth. This preserves DNA and pattern information for analysis.

Question 12Crime Scene Investigation

A CSI must collect a dried bloodstain from a non-porous surface. Which method is generally preferred to preserve the stain for DNA analysis?

  1. Swabbing the stain with a swab moistened with sterile water Correct answer.
  2. Scraping the stain into a paper envelope with a clean blade
  3. Swabbing the dry stain with a dry swab
  4. Cutting out the entire surface section

Explanation

Dried stains on non-porous surfaces are typically collected by moistening a sterile swab with sterile water and gently swabbing the stain. This maximizes recovery while preserving the sample for DNA analysis.

Question 13Crime Scene Investigation

Which of the following is the most appropriate action when a CSI discovers a potential fingerprint on a dark, non-porous surface at the scene?

  1. Dust the print with black powder and lift with tape
  2. Apply ninhydrin and heat the surface
  3. Apply cyanoacrylate fuming directly at the scene without documentation
  4. Use oblique lighting and photograph before applying any powder Correct answer.

Explanation

Latent prints should be documented in place first, often using oblique lighting to enhance visibility. Photographing before treatment preserves the original condition and allows later comparison.

Question 14Crime Scene Investigation

What is the principal risk of using the same pair of gloves to handle multiple items of evidence?

  1. Gloves degrade faster
  2. Cross-contamination between items Correct answer.
  3. Chain-of-custody paperwork becomes invalid
  4. Gloves lose their grip

Explanation

Reusing gloves transfers biological and trace material between items, creating cross-contamination. Changing gloves between items protects the integrity of each sample.

Question 15Crime Scene Investigation

A CSI is asked whether a door was locked at the time of entry. Which documentation source best addresses this question?

  1. The chain-of-custody form
  2. The scene notes and photographs taken before any alteration Correct answer.
  3. The CSI's memory of the scene
  4. The responding officer's verbal recollection

Explanation

Contemporaneous scene notes and photographs taken before alteration provide the most reliable record of conditions such as door position and lock status. They preserve the original state for later review.

Question 16Crime Scene Investigation

Which of the following best describes the correct order of operations for processing a scene?

  1. Collect evidence, photograph, sketch, then secure the scene
  2. Secure the scene, document, collect evidence, then package and submit Correct answer.
  3. Package evidence, secure the scene, then photograph
  4. Sketch, secure the scene, then collect evidence

Explanation

Processing follows a logical sequence: secure the scene, document conditions, collect evidence, and then package and submit. Each step preserves the integrity of the next.

Question 17Crime Scene Investigation

A CSI finds a footprint in soft soil near a point of entry. Which action best preserves the impression?

  1. Brush loose soil from the impression to reveal detail
  2. Cover the impression with a plastic sheet and leave it indefinitely
  3. Pour water into the impression to stabilize it
  4. Photograph with scale and cast the impression before disturbing the area Correct answer.

Explanation

Footwear impressions are documented with scale and then cast to preserve three-dimensional detail. This should occur before any disturbance to the surrounding area.

Question 18Crime Scene Investigation

Which of the following is the most important reason to record the names and times of all persons entering a scene?

  1. To calculate overtime costs
  2. To satisfy union requirements
  3. To determine which officer is in charge
  4. To establish a record of potential contamination and scene alteration Correct answer.

Explanation

A scene entry log documents who entered, when, and for what purpose, which supports contamination assessment and later testimony. It also helps identify potential sources of transferred material.

Question 19Crime Scene Investigation

Which technique is most appropriate for documenting a large outdoor scene with scattered evidence over several acres?

  1. A single close-up photograph of each item
  2. A verbal description in the report only
  3. Aerial or elevated photography combined with a grid-based sketch Correct answer.
  4. A hand-drawn sketch without measurements

Explanation

Large outdoor scenes benefit from aerial or elevated photography to capture overall context, combined with a grid-based sketch for measured positions. This provides both overview and precise location data.

Question 20Crime Scene Investigation

A CSI observes a血迹 pattern on a wall that includes both spatter and a transfer stain. Which approach best supports later bloodstain pattern analysis?

  1. Clean the wall after photographing to prevent biohazard
  2. Collect only the largest droplets
  3. Paint over the pattern to preserve it
  4. Photograph the pattern with scale and document its location and orientation Correct answer.

Explanation

Bloodstain patterns must be documented in place with scale, location, and orientation before any cleaning. This preserves the geometric information needed for pattern analysis and reconstruction.

Question 21Crime Scene Investigation

A defense attorney challenges the reliability of a CSI's scene sketch. Which feature of the sketch most directly supports its evidentiary value?

  1. The inclusion of a legend, scale, measurements, and reference points Correct answer.
  2. The use of color coding
  3. The signature of the lead detective
  4. The artistic quality of the drawing

Explanation

A sketch's evidentiary value rests on measurable accuracy: a legend, scale, measurements, and fixed reference points allow verification. These elements let others reproduce and check the recorded positions.

Question 22Crime Scene Investigation

During processing, a CSI realizes that a photograph was taken after an item had already been moved. What is the most appropriate corrective action?

  1. Ignore the discrepancy since it is minor
  2. Discard the photograph to avoid confusion
  3. Recreate the original position and photograph it as if undisturbed
  4. Note the alteration in the report and document the original position from other sources Correct answer.

Explanation

Any alteration must be disclosed in the report so the record remains accurate and transparent. Reconstructing the original position from other documentation preserves context without misrepresenting the scene.

Question 23Crime Scene Investigation

Which of the following best explains why a CSI should avoid using the same reference point for triangulating multiple items in a cluttered room?

  1. Reference points must always be outdoors
  2. A single reference point is always insufficient for any measurement
  3. A single reference point cannot be accurately measured
  4. Multiple items measured from one point may produce overlapping measurements that are difficult to verify Correct answer.

Explanation

Using one reference point for many items can create overlapping arcs and ambiguous measurements that are hard to verify. Multiple fixed reference points improve accuracy and allow cross-checking.

Question 24Crime Scene Investigation

A CSI must decide whether to collect an entire section of drywall bearing a bloodstain or to swab the stain. Which consideration most strongly favors collecting the drywall section?

  1. The wall is easily replaceable
  2. The stain is large and the pattern geometry is important to preserve Correct answer.
  3. The stain is already dry and flaking
  4. The stain is small and the surface is non-porous

Explanation

When pattern geometry or a large stain is significant, collecting the substrate preserves spatial relationships that swabbing would destroy. Swabbing is better suited to small stains where pattern is not the focus.

Question 25Crime Scene Investigation

Which of the following scenarios best illustrates a chain-of-custody deficiency that could affect admissibility?

  1. A CSI transfers evidence to a laboratory courier without recording the transfer Correct answer.
  2. A CSI uses a new pair of gloves for each item
  3. A CSI documents the time of collection in the notes
  4. A CSI photographs evidence before packaging

Explanation

An unrecorded transfer breaks the documented chain of custody, creating a gap that may be challenged in court. Every transfer must be recorded with date, time, and handler signatures.

Question 26Crime Scene Investigation

In crime scene processing, what does the term "primary scene" refer to?

  1. The staging area where the CSI team parks vehicles and stores equipment
  2. The location where the incident actually occurred and where most physical evidence is concentrated Correct answer.
  3. The nearest police facility where evidence is temporarily stored
  4. The location where a body is taken for autopsy

Explanation

The primary scene is the site of the original incident, where the greatest concentration of physical evidence is usually found. Secondary scenes are other locations connected to the incident, such as a vehicle or a dump site. Correctly identifying the primary scene guides resource allocation and documentation priorities.

Question 27Crime Scene Investigation

A CSI is assigned to a scene where a body was found in a vehicle parked in a public lot. Which designation best describes the vehicle in relation to the death investigation?

  1. An administrative zone outside the investigative scope
  2. A reference point used only for triangulation of evidence
  3. A secondary scene connected to the primary incident location Correct answer.
  4. A temporary holding area for evidence awaiting transport

Explanation

A vehicle containing a body is typically a secondary scene: it is connected to the incident but is not necessarily where the event originated. Secondary scenes require the same documentation, security, and evidence protocols as the primary scene. Recognizing this prevents investigators from treating the vehicle as mere transport.

Question 28Crime Scene Investigation

Which of the following best defines the "point of entry" at a burglary scene?

  1. The location where the suspect first gained access to the interior of the structure Correct answer.
  2. The location where the first responding officer parked a patrol vehicle
  3. The location where the victim first noticed the offense had occurred
  4. The location where the suspect exited the property with stolen goods

Explanation

The point of entry is the specific location where access to the interior was achieved, such as a forced door or broken window. It is a high-value area for trace evidence, tool marks, and latent prints. The point of exit is documented separately because it may yield different evidence.

Question 29Crime Scene Investigation

A CSI photographs a scene before any items are moved or collected. What is the primary purpose of this sequence?

  1. To capture the original condition and spatial relationships of evidence before alteration Correct answer.
  2. To create a backup in case the scene sketch is later lost
  3. To allow the photographer to leave the scene earlier than other personnel
  4. To satisfy a requirement that all photographs be taken within the first hour

Explanation

Photographing before any alteration preserves the original condition and the spatial relationships among items. Once an item is moved, that configuration can never be recreated exactly. This is why overall, midrange, and close-up photographs precede collection.

Question 30Crime Scene Investigation

Which lighting technique is most useful for revealing latent footwear impressions or dust marks on a smooth, dark floor?

  1. Oblique lighting directed at a low angle to the surface Correct answer.
  2. Direct on-camera flash aimed perpendicular to the surface
  3. Diffuse overhead lighting from the ceiling fixtures
  4. Backlighting through a translucent panel beneath the floor

Explanation

Oblique lighting, also called side lighting, rakes across a surface at a low angle and creates shadows that reveal texture and residue patterns invisible under direct light. Direct flash washes out subtle contrast on smooth surfaces. This technique is standard for dust impressions and indented marks.

Question 31Crime Scene Investigation

When photographing a scene, why should a scale be placed adjacent to an item of evidence in close-up photographs?

  1. To indicate the evidence number assigned in the scene log
  2. To provide a size reference that allows later measurement of the item Correct answer.
  3. To show which investigator collected the item
  4. To mark the boundary of the search area for the photographer

Explanation

A scale in the frame provides a known reference so that dimensions of the item can be established from the photograph. Without it, the image cannot support reliable measurement. The scale should be placed in the same plane as the item to avoid perspective error.

Question 32Crime Scene Investigation

A CSI needs to document a room containing a large amount of furniture and numerous evidence items. Which photographic approach best supports later reconstruction of the scene?

  1. A single wide-angle photograph taken from the doorway only
  2. Overall, midrange, and close-up photographs taken in a consistent sequence from multiple corners Correct answer.
  3. Aerial photographs taken from outside the structure
  4. Close-up photographs of each item without any overall views

Explanation

A systematic progression from overall views to midrange views to close-ups establishes context and then detail. Photographing from multiple corners allows the geometry of the room to be reconstructed. Close-ups without overall context lose the spatial relationships needed for reconstruction.

Question 33Crime Scene Investigation

Which of the following items is most appropriately documented with a specialized photographic technique rather than a standard visible-light photograph?

  1. A bloodstain visible on a light-colored wall
  2. A bullet casing on a carpet
  3. A latent fingerprint developed with fluorescent powder Correct answer.
  4. A footwear impression in mud

Explanation

Fluorescent powder-developed prints require an alternate light source and appropriate barrier filters to capture the fluorescence. Standard visible-light photography would fail to record the developed print adequately. The other items are visible under ordinary lighting and are documented with standard techniques and scales.

Question 34Crime Scene Investigation

What is the purpose of a placard or evidence marker placed next to an item before photography?

  1. To identify the agency responsible for the investigation
  2. To link the photographed item to its entry in the evidence log and sketch Correct answer.
  3. To show the date on which the scene was secured
  4. To indicate the estimated value of the item for property records

Explanation

Placards assign a unique identifier to each item so that photographs, sketches, and evidence logs can be cross-referenced. This consistency is essential when the case is later reconstructed or presented. Without a common identifier, records become difficult to reconcile.

Question 35Crime Scene Investigation

A CSI is sketching a room and must show the position of a chair relative to two fixed walls. Which measurement method is most appropriate?

  1. Measuring only the distance from the nearest wall
  2. Triangulation using two fixed reference points Correct answer.
  3. Pacing from the doorway to the chair
  4. Estimating distance by eye and noting it as approximate

Explanation

Triangulation uses two fixed reference points to locate an item precisely by intersecting distances. This produces a position that can be reproduced independently by another investigator. Single-distance or estimated measurements cannot reliably relocate an item in two dimensions.

Question 36Crime Scene Investigation

Which element must appear on a finished crime scene sketch to make it usable in court?

  1. The estimated dollar value of damaged property
  2. A legend and scale that identify symbols and distances used Correct answer.
  3. The home address of the assigned investigator
  4. The names of all neighbors interviewed

Explanation

A legend explains the symbols used, and a scale establishes the relationship between drawing dimensions and actual distances. Together they allow a reader to interpret and verify the sketch. Without them, the drawing is not a reliable record.

Question 37Crime Scene Investigation

A CSI uses a coordinate or baseline method to sketch a long hallway with evidence along its length. What is the principal advantage of this method here?

  1. It eliminates the need to measure any distances at all
  2. It allows the sketch to omit a legend and scale
  3. It records only the items nearest the entrance
  4. It uses a single fixed reference line from which perpendicular distances are measured Correct answer.

Explanation

The baseline or coordinate method establishes a fixed reference line, and each item is located by a distance along that line plus a perpendicular offset. This is efficient for elongated spaces where triangulation from two points becomes cumbersome. The method still requires accurate measurement and a legend.

Question 38Crime Scene Investigation

Which of the following best describes the role of a scene log maintained at the perimeter?

  1. It records who entered and exited the scene and when, supporting scene integrity Correct answer.
  2. It lists the retail price of all items removed from the scene
  3. It serves as the final investigative report submitted to the prosecutor
  4. It documents the weather forecast for the following day

Explanation

The scene log creates a chronological record of personnel and visitors entering and leaving the scene. This supports scene integrity by showing who had access and when. It is a contemporaneous record, not a substitute for the final report.

Question 39Crime Scene Investigation

A first responder moves a bleeding victim from the living room to the front porch for medical care. How should the CSI document this action?

  1. Ask the responder to sign a waiver absolving the team of documentation duties
  2. Record the original location, the reason for movement, and the new location in the scene documentation Correct answer.
  3. Ignore the movement because it was medically necessary
  4. Photograph only the porch and omit the living room

Explanation

Life-saving actions legitimately alter a scene, but the alteration must be documented to explain discrepancies between the scene and witness accounts. Recording the original position, the reason, and the new position preserves the evidentiary value of the scene. This documentation protects both the responder and the investigation.

Question 40Crime Scene Investigation

Why should a CSI avoid smoking, eating, or drinking within the established scene perimeter?

  1. These activities can introduce contamination and destroy trace evidence Correct answer.
  2. They require additional lighting that damages photographs
  3. They interfere with radio communications
  4. They are prohibited only because they distract personnel

Explanation

Smoking, eating, and drinking introduce foreign material that can contaminate trace evidence such as DNA, fibers, and residues. Ash, saliva, and food debris can also be mistaken for scene evidence. Controlling these activities is a basic contamination-prevention measure.

Question 41Crime Scene Investigation

A CSI is processing a scene in an air-conditioned room and notices the ventilation system is running. What is the most appropriate action?

  1. Increase the airflow to disperse any airborne contaminants
  2. Document the conditions and consider shutting down the system to limit movement of trace evidence Correct answer.
  3. Ignore the system because HVAC operation is irrelevant to evidence
  4. Open all windows to equalize pressure with the exterior

Explanation

Operating HVAC systems can move lightweight trace evidence and alter the scene. The conditions should be documented, and shutting down the system may preserve evidence distribution. Opening windows or increasing airflow would worsen the problem.

Question 42Crime Scene Investigation

Which of the following describes the correct way to package a wet, bloodstained garment for transport?

  1. Seal the wet garment in a plastic bag to retain moisture
  2. Air-dry the garment and package it in a breathable container such as a paper bag Correct answer.
  3. Place the garment directly into a rigid container without drying
  4. Fold the garment so the stain contacts unstained fabric

Explanation

Moisture promotes microbial growth that degrades DNA and promotes putrefaction. Air-drying before packaging in breathable material preserves biological evidence. Sealing wet items in plastic traps moisture and accelerates degradation.

Question 43Crime Scene Investigation

What is the purpose of sealing evidence containers with tamper-evident tape and initialing across the seal?

  1. To comply with shipping weight regulations
  2. To make the package easier to stack in the storage room
  3. To show that the container has not been opened or altered since sealing Correct answer.
  4. To indicate the priority level of the evidence analysis

Explanation

Tamper-evident seals with initials across the closure demonstrate that the container remained closed from sealing until the next documented opening. This supports the integrity of the evidence. Any break in the seal becomes visible and must be explained.

Question 44Crime Scene Investigation

A CSI collects a small paint chip from a floor. Which packaging approach best preserves it?

  1. Wrap it in a tissue and place it in an unsealed envelope
  2. Tape it directly to a page in the investigator's notebook
  3. Place it loose in a large plastic bag with other debris
  4. Place it in a small paper bindle or coin envelope, then seal and label the outer container Correct answer.

Explanation

Small trace items are best secured in a paper bindle or small envelope that prevents loss, then placed in a labeled outer container. Taping directly to a page risks contamination and loss of the item. Loose packaging allows the chip to migrate and be damaged.

Question 45Crime Scene Investigation

When should a CSI photograph an item before packaging it?

  1. In its original position, then again after any necessary repositioning for detail Correct answer.
  2. Only if the item is larger than the evidence marker
  3. Only when a supervisor requests additional images
  4. Only after the item has been placed in its evidence container

Explanation

Photographing in the original position preserves context, and a subsequent detail photograph captures identifying characteristics. Both stages are part of a complete documentation record. Photographing only after packaging loses the original context permanently.

Question 46Crime Scene Investigation

A CSI finds a handwritten note on a table. Which handling practice best preserves latent prints and handwriting evidence?

  1. Pick the note up by its edges or use tweezers, and package it flat between rigid supports Correct answer.
  2. Handle the note with bare hands to avoid glove residue
  3. Fold the note in half to fit a standard envelope
  4. Crumple the note and place it in a plastic bag

Explanation

Handling paper by the edges minimizes contact with surfaces that may bear latent prints. Packaging flat between rigid supports prevents creasing that could damage writing or print detail. Crumpling or folding alters the document and can destroy evidence.

Question 47Crime Scene Investigation

Which of the following is the most appropriate first action when a CSI discovers a suspicious package at a scene?

  1. Stop processing in the area, secure the immediate vicinity, and notify the appropriate specialized unit Correct answer.
  2. Spray the package with a presumptive chemical test
  3. Immediately open the package to determine its contents
  4. Photograph the package and then carry it to the evidence vehicle

Explanation

A suspicious package may present an explosive or hazardous threat, so processing must stop and the area must be secured. Specialized personnel determine the nature of the package and the safe approach. Handling or testing the package before that assessment endangers personnel and compromises the scene.

Question 48Crime Scene Investigation

A CSI must process a scene that includes a suspected clandestine drug laboratory. Which consideration is most important before entry?

  1. Determining the number of suspects involved in distribution
  2. Assessment of chemical, fire, and explosion hazards by qualified personnel Correct answer.
  3. Estimating the street value of the seized substances
  4. Locating the nearest retail supplier of laboratory glassware

Explanation

Clandestine laboratories present chemical toxicity, flammability, and explosion hazards that require specialized assessment before entry. Untrained entry can result in serious injury or death. Evidence processing proceeds only after the scene is declared safe.

Question 49Crime Scene Investigation

Which of the following best describes the purpose of a "scene security" perimeter?

  1. To restrict access to authorized personnel and protect evidence from contamination or loss Correct answer.
  2. To designate a parking area for media vehicles
  3. To mark the boundary of the agency's legal jurisdiction
  4. To provide a location for public interviews with witnesses

Explanation

The security perimeter controls access so that only authorized personnel enter the scene. This protects evidence from contamination, loss, and unauthorized alteration. Media parking and witness interviews are managed outside the secured area.

Question 50Crime Scene Investigation

A CSI is deciding whether to collect an entire window frame with tool marks or to make a cast of the marks. Which factor most strongly favors collecting the entire frame?

  1. The cast would be more expensive to produce
  2. The frame has no evidentiary value once photographed
  3. The frame can be removed without destroying the marks and preserves the original substrate for laboratory comparison Correct answer.
  4. The frame is too large to photograph at the scene

Explanation

When an item bearing tool marks can be removed without destroying the marks, collecting the whole item preserves the original substrate for laboratory comparison. Casts are a compromise used when the item cannot be removed. The decision turns on preservation quality, not cost or photography convenience.