At the forensic laboratory, every contact leaves a trace
The body tissues, fluids, body prints, shoe marks and many more are the things Rwanda Forensic Laboratory handles to provide law enforcement with scientific evidence to establish who is who in an investigation.
Between April 2018 and May 2020, the laboratory did over a thousand tests, most of them are DNA tests and the least of them are Ballistic and Tool marks the least.
Individuals and law enforcement agencies from Rwanda and over a dozen countries especially in Africa, seek the laboratory’s services to have scientific answers.
Kigali Law Tidings visited the laboratory to get a picture of how science meets the wit of investigators to identify the smoking guns in the pursuit of who is who in a crime.
Jean Pierre Samvura is the RFL spokesperson who right away said that forensic science makes investigations possible because “every contact leaves a trace” which forensic science can see.
The deoxyribonucleic acid (DNA) tests
Before Rwanda Forensic Laboratory, the Rwanda law enforcement could seek DNA tests from Europe especially Germany and Belgium which was very costly.
The genetic material determinant test is carried out on body fluids and or tissues traced at a crime scene.
“As a forensic laboratory, chewed chewing gum and spat saliva are precious sources of DNA” Samvura said.
However, in the absence of saliva or blood, investigators can look for other traces such as spots where the perpetrator’s body came into contact with objects at the crime scene.
“We can extract DNA from the sweat just in case a perpetrator’s body came into contact with anything at a place” Samvura said.
Medical detectives get challenged whenever they identify only a single spot where a perpetrator’s finger touched.
The spot would be needed for both fingerprint and the fluids of it for DNA analysis.
“There instances when a fingerprint is identified and can be used to identify the perpetrator but we also need the same spot of the fingerprint for the DNA analysis” He posed.
When one tries to extract DNA from the spot, the fingerprint can be destroyed and vise versa.
“When necessary, we use special torches to reveal the fingerprint and take its image by the camera. We then proceed to destroy the fingerprint for DNA analysis” Samvura said.
Fingerprints are never the same
Samvura explained that there are no two individuals with the same fingerprint.
“They can appear the same but a closer look into the ridges and their patterns brings a difference. DNA of identical twins can be similar but fingerprints are always different” he said.
Investigators are always many steps ahead of the crime plotters and that’s why they trace them.
“We can even identify whose shoe stepped where even if there are similar shoe marks from the same type of shoes” he said.
In case there is no blood trace
There are instances where a perpetrator leaves no trace at the crime scene especially in murder cases.
“Blood is very important especially in murder crimes, we can test it for DNA and it tells a story of how the crime was committed”
Samvura said that forensic scientists can spray a chemical known as luminal to a spot cleansed of the blood and then shut out the light.
“When it is totally dark, there appears an illumination on the spots where blood was”
The manner in which blood gets on surfaces tells much about the inflicting tool, the direction in which the perpetrator was, height and distance of the perpetrator vis-a-vis the victim.
Had it not been for the use of forensic science, many cases would remain unresolved or investigators get the wrong suspects.
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