Unit 01 · Crime Scene & Evidence Basics
This unit builds the habits every scene depends on: working a systematic search pattern and observing what is present and what is absent, keeping dated and timed contemporaneous notes, and producing a measured sketch with scale photography before anything is moved. From there you learn to recognize, collect, and package evidence without contaminating it, and to hold an unbroken chain of custody from the scene to the courtroom. Good documentation is what lets an analyst say later exactly what can — and cannot — honestly be claimed.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Systematic scene observation & search | Glances around and grabs what stands out. | Searches but misses areas or works without a pattern. | Works a defined search pattern methodically and records what is present and absent. |
| Contemporaneous notes & documentation | Relies on memory and writes it up later. | Takes notes but they are incomplete or not timed. | Keeps dated, timed, factual notes with no conclusions baked in. |
| Sketch & scale photography | Rough sketch with no measurements or scale. | Sketches or photographs but omits a scale or key measurements. | Produces a measured sketch with a north arrow and photographs every item with an L-scale before it is moved. |
| Evidence recognition, collection & packaging | Handles items bare-handed or mixes them together. | Collects but mislabels or over-handles items. | Recognizes, isolates, and packages each item in the correct container with a unique number, minimizing contamination. |
| Chain of custody | Cannot account for who held an item. | Logs some transfers but leaves gaps. | Maintains an unbroken, signed chain and can explain why a broken chain can make evidence inadmissible. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects scene documentation and evidence handling to its anchor across History · Reading · Writing and defends why the connection matters. |
“I photographed the knife with an L-scale before anyone touched it, sketched its position with measurements to two fixed points, then bagged it in its own labeled envelope and signed the custody log. What I can say is where item 4 was and that the chain never broke — not who used it. That call belongs to the court.”
“I picked up the knife to get a better look, then put it in a bag with the other stuff. It was obviously the weapon — I’ll write down where it was later.”
You demonstrate this unit by documenting a mock scene — a measured sketch, scale photographs, and a sealed evidence log — plus short oral checks where you explain aloud what your notes let you claim and what they do not. A criterion counts as mastered only when you can both do the work at the scene and defend the honest limits of your conclusions. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.