Two and a Half Hours of Daylight
A hunter reports a human skull at the base of a tree in mixed woodland 400 m from a gravel logging road. You arrive at 15:40 in late October; sunset is 18:10 and 25 mm of rain is forecast overnight. A shallow depression about 1.5 m long holds scattered bones, a running shoe, and dark clothing. A rusted shovel leans against a tree 8 m away. A partial shoe impression sits in mud at the edge of the depression. Flies are active and pupae are visible. Fresh tyre tracks are cut into the shoulder of the gravel road. The landowner says the site is 30 minutes from pavement and wants it cleared before deer season. Your team is you and two technicians; the anthropologist and entomologist are three hours away.
1. You have about 2.5 hours of daylight. Set the priority order and justify it.
Read the worked answer
Rank by perishability, not by interest.
- Secure, log, and photograph. Overall photographs and a continuous video walk-through before anyone steps into the depression. Every later step is only defensible against this baseline.
- Cover the depression. Tarp on stakes, not touching bone or clothing, to shed the forecast rain. Do this after the photographs, not before.
- Entomology. Collect now: live larvae and pupae into rearing containers, a representative sample into 80 percent ethanol, plus ambient and soil temperature and exact collection times. Rain will wash the surface insects away and the development timeline is the only rough post-mortem interval you have.
- Tyre tracks. Photograph with scale and cast now; 25 mm of rain will erase them overnight, and they connect the site to a vehicle.
- The shovel. Photograph in place, then collect - it carries soil, possible tool marks, and DNA.
- Shoe impression. Photograph and cast, water permitting.
- Do not excavate. Surface map the scatter, establish a datum, and leave the deposit intact for the anthropologist. Context is the evidence; a hurried dig destroys it. Search the access route only if time remains.
2. The shoe impression is in mud with standing water at its edge. How do you preserve it?
Read the worked answer
Photographs first, because they may end up being the primary record. Tripod, scale, oblique lighting from several angles, and a 3D scan or photogrammetry set if you have it. Then try to cast.
Remove the standing water with a pipette or a sponge working from the rim inward, never touching the impression itself. Build a dam - a flexible plastic strip or a metal frame pressed into the mud around the impression - so the casting material stays put. Mix dental stone to a thick, pancake-batter consistency and pour from the lowest edge so it flows across the impression rather than dropping onto it. Let it set fully, at least 30 minutes, then lift, gently clean, label with orientation and item number, and package so the surface is not abraded.
Do not use plaster of Paris in wet, cold conditions; it crumbles and sets too slowly. If the water cannot be controlled, cast anyway with a dam and accept a poor result rather than lose the impression to rain, and record the loss in your notes. The running shoe itself is present, so the cast corroborates position and alignment more than tread design.
3. What do you tell the landowner, and how do you handle the shovel and overnight security?
Read the worked answer
Tell him plainly that this is a potential homicide scene, that it will not be cleared before deer season, and that he must stay off the area and keep vehicles off the shoulder. Explain what will happen next and who to contact, and get his cooperation in writing if he will give it. His preference is not a legal basis for release, but his goodwill determines whether the site is intact when you return.
The shovel: photograph it in place with scale before touching it, then collect with gloves, package the blade separately to protect any soil or trace on it, and treat any adhering soil as a comparison sample. It is both a tool and a possible DNA source, and its position 8 m from the depression matters.
Overnight: the site needs a deputy, a guard, or at minimum a locked gate and a camera, plus the tarp and stakes already in place. Nothing is backfilled, and no one 'tidies' the scatter. Record the landowner's account of access, hunters, and any vehicles seen, and pass the tyre-track casts to the investigators the same night so the road can be checked while the trail is fresh.