Forensic Evidence Collection and Recovery

Answer

Forensic Evidence Collection and Recovery

It is the duty of an investigator to handle a murder crime scene carefully to ensure that all the evidence is noted, collected and carefully transported to the laboratory for testing. When done correctly, perpetrators of a crime are keenly investigated, put to trial and sentenced when proven guilty. Therefore, it is essential to carry out activities in the homicide crime scene with great observance so as to collect evidence that would possibly lead to a conviction beyond reasonable doubt. This discussion will provide an in-depth analysis of the manner in which evidence should be collected at a crime scene.

Homicide Crime Scene Evidence

Dried Blood

   A photograph of the blood stain must be taken to capture blood stain patterns pictorially. All blood stains along with their patterns must be photographed with a rule put together and added into the photograph enhancing perspective. Since a floor is impractically portable, an investigator by the aid of a fingerprint tape can lift the specimen from the crime scene putting the sticky side of the tape on the sample, then run a blunt object over the tape then gently, the investigator could remove the tape which will have some of the dried blood sample and place it carefully in a paper bag ready for transportation to the laboratory. Alternatively, the investigator could use a clean razor to scrape off the dried blood fragments and collect into a paper bag and seal it (Gardner, 2011).

Collection tools include a camera to take photographs of the blood stains in the crime scene.  A pair of gloves to prevent the investigator from tampering with the scene during collection using a fingerprint tape to avoid marking the evidence with his own hand print (Lounsbury & Thompson, 2006). A tape is used for collect blood sample on the floor through the sticky part of the tape. A blunt object, for example, an eraser for running over the placed tape to ensure contact is made with the dried stain. A clean sharp razor is used to scrape off flakes of dried blood. A permanent marking pen is used to label collected samples and packing within the bar and interfere with the evidence. Equipment like a paper packet is used to package the evidence collected. A paper packet is preferred over a plastic bag for packaging dried blood stain as a plastic bag may form moisture within the bag interfering with the evidence.

Handgun

            Condition of the handgun at the place of location has to be drawn and photographed before securing the weapon. Unload the handgun with utmost care by handling areas less likely contain specimen to preserve evidence such as fingerprints, hair or dried specimen like blood. Before removing cylinders, its initial position should be noted on cylinder top. The cartridges when removed should be handled so as to safeguard fingerprints. Each case must be separately packed then backed to the noted information. Every recording is then taken. Finally, trace any evidence like finger prints, blood dried or drying, hair strands, paint, fiber or tissue may be important. A pair of gloves must be used to prevent interference with the initial fingerprints. A camera is handy in photography of initial handgun positioning. A hand lens is necessary to observe additional evidence such as hair strands on the handgun. A marker is used to mark the initial positioning of the cylinder before removal of cases (Cunningham, 1985).

During packaging, the gun must be unloaded carefully and placed in a specially built box which has means for holding the handgun safely without tampering with the evidence and has a metallic plate to block the muzzle. It is recommended to transport firearms to laboratories personally although they can be sent by mail if they are safely packaged and unloaded.

Shell Casings

A photograph of their initial positioning must be taken. Their positions are diagramed before they are taken away and put safely for laboratory examination. Specimen such as blood, fiber, paint, fingerprints and hair are collected from the shell casing if possible. If not, they are carefully put in a paper bag and transported into the laboratory. Tools used include a camera for photography of the shell casings, a marker for diagramming shell casings positions, a hand lens magnify and identify specimen such as hair strands and paper bags to collect the shell casings and other specimen around (Davenport, Lindemann, Griffin, &Borowski, 1988).

Shell casings must be packaged separately in paper bags and carefully placed in a larger envelope then personally transported to the laboratory for testing.

Hairs

Hair can be collected by viewing the available evidence using a hand lens and carefully removed using a pair of tweezers and placed in a clean container being careful to ensure the whole strands are in the container then with other specimen transported to the laboratory for examination (Cunningham, 1985).

Lab Testing

Dried Blood

A DNA is taken from the dried paper packet to ascertain whether the blood is from the deceased victim or from any other person present at the crime scene and could give the investigators a lead on the suspect (Gardner, 2011).

Handgun

A DNA test can be done on the sample handgun such as collection of fingerprints to ascertain the lead suspect. Hair strands, if any, can also be collected and tested then used to match that of the suspect (Davenport, Lindemann, Griffin, &Borowski, 1988).

Shell Casings

Shell casings may contain the DNA of the suspect such as the finger prints, hair strands or paint and fiber. It is therefore worthwhile to collect shell casings as they may link the investigators to the crime perpetrators.

Hairs

Three major analyses are performed by forensic scientists on the hairs found in the scene of the accident. Firstly, chemical analysis must be done to prove presence of hard metal an indication of use of any illegal drug in the body of the suspect. Secondly, the investigator looks out for DNA found on the root hairs because of the cells it contains to give them the DNA of the suspect. Hair can be the victim’s or the suspect’s so the position the hair is found and the DNA test result proves it. Furthermore, when hair is directly moved from the part of the body it is from it is considered as a primary transfer as these hairs result from clothing, and other items in the home but when hair is secondarily transferred, presence of animal hairs can be noted in the home of pet owners and in such environment can be used to link suspects to the crime scene (Cunningham, 1985).

Conclusion

            In conclusion, crime scenes when handled with care and samples thoroughly tested, can lead to perpetrators of crime being arrested charged and convicted thus justice being served.