Integrated Evidence Collection Practical: Full Scene Simulation

Objective. Working individually, students will process a staged multi-evidence crime scene from arrival through evidence submission, producing a complete, legally defensible evidence package—search pattern documentation, collection notes, chain-of-custody forms, and packaged items—with no critical errors.

This lab brings together every skill you have built in this course. You will process a staged crime scene from first arrival to property-room submission—alone, under time pressure, with no prompts. Every decision you make will be evaluated against the same standards used in real casework and assessed by credential-exam rubrics.

Before You Touch Anything: Scene Safety and PPE

Scene safety is not a formality. A contaminated technician can compromise evidence, injure themselves, and expose an agency to liability. Follow this sequence every time:

1. Pause at the perimeter. Look for physical hazards—unstable structures, biohazard indicators, chemical odors, sharps.

2. Don full PPE before crossing the tape. For this simulation that means gloves (at least two layers so you can remove the outer pair after handling each major item), Tyvek suit, shoe covers, eye protection, and mask. Change outer gloves between each evidence item to prevent cross-contamination.

3. Establish and respect the inner and outer perimeters. No unauthorized personnel enter the inner perimeter. You are the only technician; keep your equipment staged outside until needed.

4. Never eat, drink, or touch your face while in the scene. Remove contaminated PPE correctly—peel gloves inside-out, dispose in a sealed biohazard bag.

The Walk-Through and Search Pattern

Conduct a silent walk-through before collecting anything. Use it to identify evidence items, decide on a search pattern, and plan your photography sequence. Document your chosen pattern on your rough sketch before you begin the systematic search.

For an indoor scene of limited size, a grid or zone pattern gives overlapping coverage. For a narrow outdoor corridor, a strip/lane pattern works. Record your choice and the reason on your scene notes—the debrief will ask you to justify it.

Photography and Sketching Before Collection

For each evidence item, shoot three photographs in sequence:

Overall: shows the item in context of the room or scene.
Mid-range: shows the item relative to a fixed landmark (door frame, wall corner).
Close-up: fills the frame with the item; include a scale ruler for size reference.

Your rough sketch must record room or area dimensions, north arrow, scale or notation that it is not to scale, your name, date, case number, and the location of every flagged item keyed to an item number. Measurements should be taken by the rectangular coordinate or triangulation method depending on whether straight-wall reference points are available.

Collection Technique by Evidence Category

This scene contains six evidence categories. Match your technique and container to the category—a wrong container is a critical error on the rubric.

| Category | Technique | Container |

|---|---|---|

| Biological swatches (dried stain) | Swab with sterile cotton swab moistened with distilled water; air-dry completely before sealing | Paper envelope or breathable evidence bag—never plastic, which traps moisture and promotes DNA degradation |

| Trace fibers | Tape lift or forceps; avoid touching with bare fingers | Paper fold (druggist fold) inside an envelope, or a sealed glass vial |

| Shoe impression (3-D in soil) | Photograph first; cast with dental stone if instructed; allow to cure fully before moving | Rigid cardboard box, cast side up |

| Digital dummy device | Handle by edges; place in a Faraday bag or static-shielding bag to block wireless signals | Anti-static/Faraday evidence bag, sealed |

| Documentary evidence (paper) | Handle with gloves; if latent prints are possible, handle minimally at edges | Paper envelope or paper bag—not plastic if latent prints are suspected and the item needs to breathe |

| Toolmark coupon (metal surface) | Do not attempt to cast in this sim; photograph with oblique lighting and a scale | Rigid box or padded envelope to prevent contact with other surfaces |

Chain of Custody: Complete It at the Moment of Collection

Chain of custody is the documented record showing who had an item, when, and why. A gap in the chain can make an item inadmissible. Complete each entry at the moment you seal the package, not at the end of the scene. Required fields for every item:

Case number and item number
Description of item (brief but specific: color, size, location found)
Date and time of collection
Collector's name, badge/student ID
Condition of item when collected
Signature and printed name

When you transfer the package to the simulated property room, both you and the intake officer (instructor) sign and record the time. That transfer entry is as important as the original collection entry.

Submitting to the Property Room

Present your packaged items in item-number order. Each package must be sealed with evidence tape that crosses the closure and bears your initials, the date, and the case number written across the tape-to-package boundary. Any package that can be opened without breaking the seal or your signature is considered unsecured—an automatic deduction.

Debrief and Self-Assessment

After submission, the instructor will ask you to explain at least three collection or packaging decisions. Refer to your notes; do not guess. Then complete the self-assessment checklist, scoring yourself honestly before you see the instructor's rubric. Comparing the two assessments teaches you to calibrate your own judgment—a skill that matters throughout your career.

Connecting to Your Credentials

The IAI CCSI exam tests your ability to articulate why each procedure is performed, not just that it was performed. The State Evidence Tech Cert requires demonstrated competency in chain-of-custody procedures. Every decision you document today is practice for those assessments.

Key terms10

Chain of CustodyThe chronological, documented record of every person who collected, handled, transferred, or analyzed a piece of evidence, used to prove in court that the item was not altered or contaminated.

Critical ErrorA mistake serious enough to render evidence inadmissible or compromise a prosecution, such as placing biological evidence in an airtight plastic container or leaving a chain-of-custody transfer undocumented.

Druggist FoldA method of folding paper into a self-closing packet used to contain trace evidence such as fibers or glass fragments, preventing loss or cross-contamination.

Faraday BagA shielded enclosure that blocks electromagnetic signals, used when collecting digital devices to prevent remote data wiping or network communication that could alter evidence.

Grid Search PatternA systematic scene search in which an area is searched in one direction and then again at a 90-degree angle, providing overlapping coverage that reduces the chance of missing evidence.

Oblique LightingA photography technique in which the light source is held at a low angle to the surface, causing three-dimensional features such as toolmarks or footwear impressions to cast shadows that reveal detail.

PerimeterA physical boundary established around a crime scene to control access; the inner perimeter surrounds the core evidence area and the outer perimeter controls public and media access.

Rectangular Coordinate MethodA scene-measurement technique that locates an evidence item by measuring its perpendicular distances from two fixed walls or baselines, used in rectangular indoor spaces.

Evidence SealTamper-evident tape applied across the closure of a packaged evidence item, bearing the collector's initials, date, and case number written across the tape-to-package boundary so any opening is apparent.

Triangulation MethodA scene-measurement technique that locates an evidence item by measuring its distance from two fixed, known reference points, useful in outdoor or irregularly shaped scenes lacking straight-wall references.

In class: Each student receives a scene briefing card and independently conducts a scene safety assessment, dons PPE, selects and executes a search pattern, documents the scene with a rough sketch, and flags all evidence items before touching anything. · Collect, package, label, and seal each evidence item found using the correct technique and container for its category; complete a chain-of-custody entry for every item at the moment of collection. · Submit the complete evidence package to the simulated property room (instructor), undergo a structured verbal debrief in which the instructor questions collection and packaging decisions, and complete a self-assessment checklist comparing performance to course standards.
Materials: Staged scene with planted evidence (biological swatches, trace fibers, shoe impression, digital dummy device, documentary evidence, toolmark coupon); full PPE kit; evidence collection toolkit; chain-of-custody forms; packaging materials; property-room intake forms; self-assessment checklist; camera.
Check: Instructor scores using a 40-point integrated rubric: PPE compliance (5 pts), search pattern execution and documentation (5 pts), correct collection technique per item (10 pts), correct packaging and labeling per item (10 pts), chain-of-custody completeness (10 pts); pass = 32 of 40 points (80%) with no critical error (wrong container for biological evidence, missing seal, or undocumented transfer).

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.