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Crime Scene and DNA Basics for Forensic Analysts

Reference Sample Collection

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Reference samples should be collected from individuals who might be linked to the crime scene where DNA evidence is found. Reference samples can be used for elimination or comparative analysis. For example, buccal swab samples taken from the suspect and/or victim, a known source, should be compared to biological evidence found at the crime scene to eliminate or place them at the scene.

Procedures for Reference Sample Collection

Type of Collection


Buccal Swab

Sterile swabs or other buccal collection devices are rubbed against the inside cheek of the individual's mouth to collect epithelial cells for analysis.

Liquid Blood Samples

Generally collected in purple topped vacuum tubes that contain the preservative ethylenediamine tetraacetic acid (EDTA).

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