Consider the following list of evidence to be processed for latent fingerprints.

Question

Consider the following list of evidence to be processed for latent fingerprints. Please write a paper detailing how you would process and recover the latent prints from the items. Clearly explain: 1) why you chose these methods rather than other means of processing and, 2) if the methods you chose would be different if you were operating in the field versus working in a controlled laboratory environment and why. Please consult the associated rubric before you begin.

1) A handgun recovered from the bottom of a lake (properly submitted in a sealed bucket of the water from which it was recovered).

Explanation / Answer

Criminal offenders have a fundamental goal notvto leave any traces at the crime scene.Some may suppose that items recovered underwater will have no forensic value.So they try to destroy the traces by throwing items in water.These traces are subjected to the destructive environmental effects.This can represent the challenge for forensic experts investigating fingerprints.

The quality of the developed fingerprints depending on the used method was assessed.The other factors like nature of aquatic environment and length of submerged time also affects the result.Therefore,latent fingerprints should deposite on metallic,plastic and submerged in fresh and sea water for 1,2 and 10 days.After recovery the items were processed by black powder,smal particle reagent and cyanoacrylate fuming and the prints were examined.Each prints was evaluated according to fingerprint quality assessment scale.

Cyanoacrylate developes latent prints found to have the highest mean visibility score after submersion in fresh and sea water for 1,2 and 10 days.Mean visibility score of prints develops showing significant decline after 10 days of submersion.Prints submerged in fresh water shows significantly higher mean than those submerged in sea water using various methods of deveopement and all time intervals.

Several studies shows that it is possible to recover latent prints submerged in water on different dry non porous surfaces with the best visualization method using cyanoacrylate either in fresh or sea water.The duration of submersion affects the quality of fingerprints developed,the longer the duration,the worse the quality is.Sea water(high salinity) has more damaging influence on the quality of detected fingerprints.

It is concluded that any piece of evidence recovered from underwater should be tested for prints,no matter the amount of time spent beneath the surface.

Black powder:Black powder is one of the first and most common methods of latent print detection.It is composed of a ceriety of carbon based powders with the binder added for stability.Finely divided particles physically adhere to water and oily residues of fingerprints.

Small particle reagent(SPR):SPR is suspension of molybdenum disulfide(MoS2) in a detergent solution.SPR works by physical adhesion to fatty residues forming a grey deposite.SPR is available commercially in a pre-mixed liquid form.SPR is most suitabe method of latent print development on non porous surfaces especially on wet surfaces,although it seems to perform equally well on dry and wet surfaces.

Cyanoacrylate:Since late 1970s,cyanoacrylate fuming continues to be adaptable,effective and popular development technique on almost all non porous surfaces and some porous surfaces.Cyanoacrylate vapous is selectively attracted to fingerprint residues to form a hard,white polymer known as poly-ethylcyanoacrylate.Fully developed CA prints are white three dimensional matrix,often visible to the unaided eye,and can be further enhanced with variety of techniques.This method should be done in an enclosed space to enclose fumes because oxygen is considered a terminating agent for the polymerization process.Fuming with cyanoacrylate can be achieved by several means,ranging from inexpensive home made chambers to large expensive commercial units.

On the basis of studies,CA was found to be the best technique used for development of latent fingerprints on different dried studied materials recovered from fresh or sea water.

Home made cyanoacrylate fuming chamber can be used as its is cheap easy and it could be made form available items.

Study shows that successful recovery of good and very good quaity of latent fingerprints is possible following submersion in different aquatic environments.In crime scenes it is unlikely that fingerprint processing and enhancement takes place immeditely after deposition especially in underwater crime scene.Therefore,fingerprints were examined at different intervals of 1,2 and 10 days.

The particular method or methods used and the order in which they are applied also depends upon the nature (porous,semiporous,nonporous) and condition (wet,dry,dirty,sticky etc).

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