US Forensic Laboratories and Evidence Submission

• Distinguish laboratory capability from submission eligibility.
• Draft a focused examination request and identify missing comparison material.
• Explain why examination order, item condition and custody records matter.

The FBI Laboratory Division supports FBI investigations and law-enforcement partners through specialist forensic work. State and local services have their own areas of responsibility. Do not assume that an agency’s reputation, a nearby address or an accreditation certificate establishes eligibility for a particular submission.

Texas DPS publishes submission guidance and service-area information. Georgia’s Division of Forensic Sciences states that it does not perform analyses for private individuals or corporations. These examples show why an examiner must read the intended recipient’s policy rather than apply a single nationwide submission rule.

A useful request identifies the questioned item, its recovery location and the issue to be tested. “Compare the paint fragment from the window frame with the supplied vehicle sample” gives more direction than “test for evidence.” State what is known, what remains uncertain and which findings could distinguish competing explanations.

Supply relevant case information without presenting an allegation as an established scientific fact. Identify reference samples separately from questioned samples. Explain who collected them and from where. Ask the laboratory which controls, elimination samples or additional material it needs; their suitability depends on the method and question.

A single object may carry biological traces, fingerprints, fibres and digital information. A treatment or sampling action useful for one discipline can change material needed by another. Agree priorities with the relevant specialists before cleaning, chemically treating or destructively sampling the exhibit.

For limited material, record the purpose of the proposed test, what it may consume and what will remain. Resolve required approvals through the case’s legal and organisational procedures. There is no universal rule that DNA, fingerprints or any other discipline must always come first.

• Keep questioned and known items separately identified and protected against transfer.
• Follow the receiving laboratory’s specimen-specific packaging, storage and hazard instructions.
• Record collection, sealing, transfers and any changes in condition.
• Confirm special arrangements for firearms, chemicals, biological hazards or unusual-sized exhibits before transport.

A damaged seal, mismatched identifier or unclear examination request requires a documented response. The appropriate action may be clarification, controlled acceptance, restricted examination or return under the laboratory’s policy. Repacking must not erase the original condition or make a broken seal appear intact.

A chain-of-custody record describes possession and handling. It cannot show that every earlier stage was contamination-free, that the specimen was representative or that collection was lawful. Those questions need their own records and assessment.

Check which exhibits were actually examined, which methods were used and whether any work was deferred or impossible. “No result” may reflect insufficient material or a method limitation; it is not automatically evidence that contact never occurred. Follow up a changed interpretation through a documented supplementary request.

Evidence Collection and Chain of Custody. US Expert Testimony and Forensic Evidence.

• Choose a laboratory by eligibility and capability, not prestige.
• Give the receiving scientist a question, suitable material and relevant context.
• Agree sequencing and document condition changes.
• Custody, scientific validity and legal authority are separate issues.