U.S. Department of Justice, Office of Justice ProgramsNational Institute of JusticeThe Research, Development, and Evaluation Agency of the U.S. Department of Justice

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Microscopic Procedures

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The following should be addressed prior to any microscopic comparisons:

Review laboratory protocols, as needed.
Complete administrative requirements:
- Chain of custody
- Marking of evidence
- Laboratory case identifiers
- Investigative file identifier
- Examiner identity
- Quality assurance
Follow laboratory safety protocols.
Determine the presence of trace evidence and follow laboratory protocol for collection.

Examples of trace evidence include
- paint,
- glass,
- blood,
- bone,
- soft tissue,
- hair,
- fibers,
- wood,
- metal smears,
- masonry,
- stone.
Determine if latent fingerprint examinations should be performed prior to toolmark examinations.
Determine if other examinations (not requested) should be performed. If so, coordinate with the investigator.
After the requirements dictated by trace evidence and latent fingerprints have been addressed, the toolmarked area can be cleaned:
- Paint may be removed by soaking the tool in alcohol or acetone.
- Plaster may be removed by soaking the tool in 15 percent acetic acid.
- Loose material may be removed by rinsing the tool in water or methanol.
- Blood and other biohazards may be removed by soaking for at least one minute in a 10 percent bleach solution.

Click here to read a sample forensic worksheet and report -
Toolmark Identification (Tools & Toolmarks)

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