Forensic science: chain of custody: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Forensic Medicine · Forensic science: chain of custody

Sample item

At a murder scene the police collect a blood-stained knife for the forensic science laboratory. Which handling best preserves its evidentiary value?

APack it in a labelled, sealed container and record every handover to maintain an unbroken chain of custodyBMark the blade with ink directly and handle it with bare handsCWash the blade to remove contamination before packingDSend it loose, without a record of who held it

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Pack it in a labelled, sealed container and record every handover to maintain an unbroken chain of custody

Physical evidence must be handled so that its identity and condition can be shown in court. Packaging, sealing, labelling and signed transfers establish the chain of custody. Washing, direct marking and unrecorded handling destroy or contaminate the trace evidence.

Option by option

A. Pack it in a labelled, sealed container and record every handover to maintain an unbroken chain of custody (correct)
Correct. A sealed, labelled exhibit with documented transfers is admissible and reliable.
B. Mark the blade with ink directly and handle it with bare hands
Bare hands add the handler's DNA and prints and ink may damage traces.
C. Wash the blade to remove contamination before packing
Washing destroys blood and fingerprints.
D. Send it loose, without a record of who held it
Without a record the identity of the exhibit can be challenged.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is A, Pack it in a labelled, sealed container and record every handover to maintain an unbroken chain of custody. Physical evidence must be handled so that its identity and condition can be shown in court.

Why is "Mark the blade with ink directly and handle it with bare hands" not the answer?

Bare hands add the handler's DNA and prints and ink may damage traces.

Why is "Wash the blade to remove contamination before packing" not the answer?

Washing destroys blood and fingerprints.

Why is "Send it loose, without a record of who held it" not the answer?

Without a record the identity of the exhibit can be challenged.

What concept does this question test?

It tests Forensic science: chain of custody in Forensic Medicine. Packaging, sealing, labelling and signed transfers establish the chain of custody. Washing, direct marking and unrecorded handling destroy or contaminate the trace evidence.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Forensic science: chain of custody?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.