Trauma and Crime Scene Technician common mistakes
Trauma and Crime Scene Technician · Understand the traps and how to avoid them.
Entering a scene and beginning documentation before establishing and verbalizing a safety perimeter, personal protective equipment level, and hazard assessment, then treating safety as a one-time checkbox rather than a continuous reassessment during the walkthrough.
Candidates memorize safety as a list to recite but do not internalize it as a gating decision; exam items that embed a hazard (a running generator, a suspected clandestine lab, a sharps container, a hostile crowd) are answered by proceeding to evidence tasks because the candidate is task-focused and wants to demonstrate technical competence.
What to do instead
Practice a fixed pre-entry sequence you can state aloud: identify hazards, set perimeter and entry control, select PPE, establish decontamination and a safe staging point, designate a safety officer. When an item introduces a new hazard mid-scene, the correct answer almost always pauses evidence work to reassess safety and document the decision. Drill items where the right answer is to stop, withdraw, and request specialized resources.
Selecting PPE and decontamination steps by habit (for example, gloves only for a blood-bearing scene, or reusing gloves between items) instead of matching PPE to the specific exposure route and choosing the correct order of doffing and decontamination.
Candidates conflate 'biohazard awareness' with 'wear gloves' and underestimate fomite and aerosol routes; they also have not practiced the sequence logic, so doffing-order items feel arbitrary and are answered by guesswork.
What to do instead
Learn the doffing hierarchy (most contaminated to least, hand hygiene between steps) and map PPE to routes: splash to face and mucous membranes, aerosol to respiratory protection, percutaneous to cut-resistant and impermeable layers. For each scenario, justify the PPE choice by naming the route of exposure and the task generating it. Treat gloves as single-use per item or per contact zone.
Walking a scene without a defined search pattern or path, contaminating or destroying trace and impression evidence by stepping through it, and failing to record the original condition and access routes before anything is moved.
Candidates prioritize visible, high-value evidence (weapons, bodies, blood) and move directly toward it, and they have not rehearsed the discipline of a controlled entry path, so the exam's 'what do you do first' items catch them choosing collection over scene control.
What to do instead
Commit to the order: secure, assess, photograph the scene as found, establish a path and search pattern, then document and collect. On any sequencing item, ask whether the proposed action changes the scene irreversibly; if so, documentation or control must come first. Practice naming the specific search pattern (lane, grid, spiral, zone) and why it fits the scene geometry and evidence type.
Treating chain of custody as a form filled out at the end, omitting transfers, leaving time gaps, using ambiguous descriptions, or failing to record who had the item at each moment including temporary custody at the scene.
Candidates see custody paperwork as clerical rather than evidentiary, and they underestimate how a single unexplained gap becomes the basis for a challenge to authenticity; exam items that hide a gap in a custody narrative are missed because the candidate reads for the item's existence rather than the completeness of its history.
What to do instead
Learn the required elements of a custody entry (unique identifier, description, quantity, collector, date and time, location, each transfer with signatures) and audit every hypothetical narrative for gaps, illegible entries, and unsigned transfers. Remember that the weakest link, not the strongest, defines admissibility; when an item shows an unrecorded interval, the correct response is to flag and document it rather than assume it is harmless.
Overlooking transient, microscopic, or easily lost evidence because attention is drawn to the obvious, and failing to recognize evidence categories that require different handling (latent prints, trace, digital, impression) at the point of recognition.
Recognition is taught as a list of evidence types rather than a habit of scanning for what the scene implies should be present; candidates also do not connect recognition to handling, so they miss items whose significance is that they demand a specific collection method.
What to do instead
Use an expectation-based scan: reconstruct the event, then ask what should be present and is not, and what is present that should not be. Build a mental checklist of categories (biological, latent print, trace, impression, digital, questioned documents, weapons and tools) and for each note the correct handling constraint at first sight, before anything is touched or moved.
Choosing a collection or packaging method that preserves the item's form but destroys or degrades its evidentiary value, such as packaging damp biological evidence in sealed plastic, air-drying incorrectly, or using the wrong swab or substrate for a surface.
Candidates memorize 'bag and tag' as a universal rule and do not internalize the moisture, cross-contamination, and degradation principles that override packaging convenience; they also confuse preservation of the physical object with preservation of the evidence on it.
What to do instead
Anchor on principles: dry before sealing biological evidence, breathable packaging for damp items, separate packaging per item to prevent cross-transfer, minimize handling and substrate disturbance, and label with orientation and condition. For each item type, state the failure mode you are preventing (mold, degradation, transfer, loss) and let that drive the method rather than a default routine.
Photographing evidence without a scale, without overlapping and establishing shots, with inconsistent lighting or angle, or failing to photograph an item in place before moving it, and treating video as a substitute for still documentation.
Candidates focus on getting a recognizable image rather than a measurable, verifiable record, and they underestimate how documentation items test whether the photo set can prove location, scale, and orientation without the photographer present to explain.
What to do instead
Use a fixed shot sequence: overall, midrange, close-up with and without scale, plus orientation reference, and document camera settings, lighting, and scale use in notes. Ask of every hypothetical photo set whether a stranger could locate the item and judge its size and orientation; if not, the set is deficient. Treat video and mapping as supplements requiring their own calibration, reference points, and documentation.
Developing or lifting latent prints without first considering the substrate and the sequence of techniques, or handling print-bearing surfaces in a way that destroys ridge detail before processing, and failing to document the processing method and result.
Candidates learn techniques as a menu rather than a decision tree keyed to surface type, porosity, and moisture, and they forget that processing is destructive and must be sequenced from least to most aggressive and coordinated with other evidence collection.
What to do instead
Memorize the substrate-to-technique logic (porous versus non-porous, wet versus dry, adhesive, skin, and so on) and the principle of least destructive first. Always sequence print processing relative to DNA and trace collection so one does not destroy the other, and record the technique, reagent, date, and outcome for every attempt, including negatives.
Interpreting bloodstain patterns by naming a category from a single stain or a single photograph without accounting for angle of impact, directionality, point of origin, and the physical mechanism, and confusing impact spatter with cast-off, expiration, or transfer.
Candidates memorize pattern names and match on visual similarity, skipping the geometric and physical reasoning that distinguishes mechanisms; they also overstate certainty, which is exactly what exam items test with ambiguous or mixed patterns.
What to do instead
Work the reasoning chain every time: characterize individual stains (size, shape, distribution, direction), compute or estimate impact angle from stain shape, establish convergence and origin in three dimensions, then infer mechanism and sequence. When the pattern is mixed or the data are insufficient, the defensible answer states limits and what additional analysis would resolve it rather than committing to a label.
Confusing the technician's role with the medical examiner's or investigator's role, offering cause or manner of death opinions, or misstating the sequence of injury documentation, body handling, and scene-to-morgue transfer of authority.
Candidates blur the boundary between documenting findings and interpreting them, and they have not learned the jurisdictional rules on who pronounces death, who authorizes movement of a body, and what the technician may and may not conclude.
What to do instead
Learn the role boundaries explicitly: the technician documents, preserves, and reports observations; cause and manner determinations belong to the medicolegal authority. For injury documentation, describe location, size, shape, and character objectively and avoid diagnostic labels. Know the local rule for body removal authorization and chain of custody for personal effects, and answer role-boundary items by identifying the correct authority rather than the most medically fluent option.