Evidence Collection

Fingerprint Evidence

Fingerprints can practically be found on any solid surface, including the human body.   Fingerprints are classified in three categories depending on the surface type they are found and on their visibility (Dutelle, 2014). Fingerprints on soft surfaces are likely three-dimensional plastic or folded prints. Fingerprints on the hard surfaces are either patent or latent. The patent is visible while the latent is invisible.

The technician will be tasked with the duty of discovering the areas that may be used for the fingerprint and in most cases, the latent impression. It starts with the entry point and works the way to the crime scene surrounding (Dutelle, 2014). The search is to discover items that might have been handled moved or anything out of place. The most suitable surfaces are non-absorbent, smooth, non-porous, and hard. It requires patience, experience, and common sense to have them all the latent impressions collected.

The recovery of the latent impressions occurs through several products to the task. The conventional methods consist of mechanical, chemical development, cyanoacrylate, and alternate light sources. The patent fingerprints have a straightforward method of the collection, which is photography. The prints are photographed in a high resolution with a measurement scale of forensic in the image for reference. The latent prints have the mechanical technique that uses a brush, and the powder in dusting the surface, physically allowing the powder to stick to contaminates, causing ridge deposits (Fish et al., 2013). The chemical technique is done in a laboratory under controlled conditions.

The use of cyanoacrylate or superglues involves fuming the scene with vapor then applying powder or stains. The vapors will adhere to any printmaking it visible under oblique ambient light. The other process would be the use of the alternate light source, which involves the use of the LED or laser rays (Dutelle, 2014). From the image, some of the devices have filters that provide various spectra that can be photographed or processed with powder and dye further.

DNA

Processing a crime scene to collect evince will mean taking the management of the scene until the time for the evidence collection. Collecting DNA in a crime scene will be difficult since they are prone to contamination. Moreover, identification requires an in-depth study and evaluation of the scene before coming up with the idea of spots of the evidence (Dutelle, 2014).  The task force must be ready to prevent the contamination and loss of continuity. In that case, the process will have to take the STAIR procedure and quickly but exceptionally manage the scene of the crime. The process will entail taking notes of the area and discovering the main points of search, making a discovery, and then collection.  

The technological advancement has made it possible to analyze the smaller biological samples in the development of the DNA profile. The DNA can be found from the touched objects or surfaces in which the skin cells may be left behind (Fish et al., 2013). The samples can be found from the bruises or skin where they were handled roughly, there should be known biological samples, known as the reference sample, available to present a side by side comparison. In some circumstances, the DNA sample is taken as a routine from the suspect in the booking and fingerprinting process.

Reference

Dutelle, A. W. (2014). An introduction to crime scene investigation. Jones & Bartlett Publishers.Fish, J. T., Miller, L. S., Braswell, M. C., & Wallace Jr, E. W. (2013). Crime scene investigation. Routledge.