Intro to Criminalistics DB5

Criminalistics DB5

Name

Class

Date

Professor

Sexual Assault Crime Scene

When a sexual assault occurs it is essential to ensure the evidence left behind by the rapist can be collected to identify the offender and to use against the offender in court. Because this evidence is biological it is extremely delicate so it must first be properly preserved, documented, and then collected. Two important pieces of physical evidence likely to be left behind after a rape is hair and semen. Semen and hair can continue improtnt DNA which can point to the suspect or match to a known suspects. Collecting this evidence properly is essential to developing potential DNA evidence once it reaches the lab.

Once the crime scene is preserved and properly documented the collection process begins. The proper protocols for collecting evidence on bedding is when possible to collect all of the bedding carefully and place it in a large evidence bag in order to be transferred to the lab. By gathering the bedding and bringing it to the lab it can be better preserved. The bedding can be examined at the forensic lab or hairs, blood, semen, sweat, etc. When transporting the bedding it should be kept in a cool place due to potential DNA evidence and kept cool when it reaches the lab (Police One, 2006). Any blood or hair will be analyzed for DNA.

Once the bedding reached the lab it would be vacuumed for any hairs or fibers that can be used to match to a criminal suspect. When the hair does not contain the root shaft any DNA profile will be incomplete but the hair is still essential for the use in the microscopic comparison. When comparing hairs certain characteristics of the hair can be compared and used to identify or eliminate a criminal suspect. Any DNA located on the bedding will be cut out and then analyzed for DNA. If DNA evidence is located it can be entered into CODIS for comparison to other DNA profiles in the database. CODIS or the Convicted Offender Index collects DNA profile of known criminal offenders (CODIS, 2013). If the rapist has committed and been convicted of a previous crime there DNA profile will be in the database.

References

National Institute of Justice. (2013). DNA Evidence: What Law Enforcement Officers Should

Know. Retrieved September 17, 2014 from https://www.ncjrs.gov/pdffiles1/jr000249c.pdf

Police One. (2006). Investigating rape crimes, Part 2: Evidence collection and analysis.

Retrieved September 17, 2014 from

http://www.policeone.com/police-products/investigation/evidence-management/articles/