Collecting Evidence
Collecting Evidence
Processing Fingerprints
“A Simplified Guide to Fingerprint Analysis” lists three types of prints that can be lifted at a crime scene (2013). They are as follows: (Note: all information in this section comes from this article).
Soft surface prints. These 3-dimensional plastic prints are found in soap, wax, wet paint and fresh chalk.
Hard surface prints. The prints fall under two categories.
Patent Prints (Visible)
Found on smooth, rough, porous (paper, cloth, wood), and nonporous (metal, glass, plastic) surfaces.
Can be found in blood, dirt, paint and ink.
Collecting patent prints is done by high-resolution photography. To improve the quality of the photograph, low angle lighting, alternative light sources, chemicals and dyes are used.
Latent Prints (Invisible)
These are when the body’s natural oils and sweat are deposited on other surfaces.
There is a greater potential of recovery if they are found on smooth, less porous surfaces.
These require fingerprint powder, chemical agents and alternative light sources to life.
Collecting latent prints can be done by dusting, then photographed, and lifting with adhesive tape. Care has to be taken with fingerprint powder as it can contaminate the evidence.
Now let us take this information and apply it to the study case. The following will list print type, reason for collection and processing method.
Murder or Witness
According to Gray, “when identifying a suspect, the more certain an eyewitness is, the more accurate they are likely to be” (Gray, 2015). So in order to eliminate or assess who is a potential suspect among witnesses, the following should occur:
When interviewing “witnesses” consider who is most confident in their details. Who is able to say for certain what they saw, experienced, heard and so on, and in doing so, admits with honesty when they did or did not do the same.
Consider that while eyewitnesses can be reliable, they can also be affected in experience when a traumatic event takes place (Gray, 2015).
In order to “protect [the] innocent, it is important to realize that an initial low-confidence ID is untrustworthy” (Gray, 2015).
When all items in the above paragraph and list are considered, then it should be much easier to weed out who is more likely a suspect, someone of interest or only a witness.
Packaging Fingerprints
After fingerprints that are transportable are collected they should be “packaged in paper bags or envelopes” and set to the lab immediately (Schiro, 2016). Transportation should be secure and extreme temperatures should be avoided.
References
A Simplified Guide to Fingerprint Analysis. (2013). Retrieved from http://www.forensicsciencesimplified.org/prints/how.html
Geberth, V. J. (November 2003). The Homicide Crime Scene. Law and Order 51(11). Retrieved from http://www.practicalhomicide.com/articles/HomCrimeSc.htm
Gray, R. (23 December 2015). It was definitely them! Eyewitnesses are more reliable when identifying suspects if they feel confident in their answer. Retrieved from http://www.dailymail.co.uk/sciencetech/article-3372109/It-definitely-Eyewitnesses-reliable-identifying-suspects-feel-confident-answer.html
Howell, J. M. (March 2001). Homicide Investigation Standard Operating Procedures, pp. 1-19. Retrieved from http://www.policeforum.org/assets/docs/Free_Online_Documents/Homicide/homicide%20investigation%20standard%20operating%20procedures%201999.pdf
Schiro, G. (2016). Collection and Preservation of Evidence. Retrieved from http://www.crime-scene-investigator.net/evidenc3.html
