The police and the FBI work hand in hand to solve the murder case that befell 4 University of Idaho students, which has become a national concern. Here's how they caught the perpetrators armed with DNA analysis, we quoted from USA Today:
Discovery of DNA traces
According to court documents made public, investigators were able to trace the DNA of a man, which was left on the knife sheath. The holster was found near one of the victims at the crime scene.
Investigators through CCTV cameras managed to find a vehicle that is believed to belong to the perpetrator and cellphone analysis showed that he was often at the location.
FBI agents then visited the trash at the residence of a suspect named Bryan Kohberger. They were able to identify the DNA in the trash as belonging to the perpetrator's father, which matched the DNA on the knife sheath.
The method and technology used to capture Kohberger is conventional DNA profiling techniques using what is known as Short Tandem Repeat (STR) analysis. This method is used for everything from identifying suspected criminals to conducting paternity tests.
What type of DNA is used?
DNA is present in every single cell of the human body and can be traced in a number of ways, including through saliva, blood and sweat. In this case, Daniel Podini, an expert from George Washington University, said the DNA in the sheath could come from a number of different cell types or a combination, including touch or traces of DNA involving a small number of skin cells.
"When we touch an object, we deposit some of our cells. There may be some skin cells, there may be saliva cells because we just coughed into our hands," said Podini.
How to link the suspect's DNA to his father?
Everyone inherits 50% of their DNA from their biological mother and biological father. Investigators picked up trash at the suspect's parents' residence, possibly objects such as plastic spoons or razors, to extract and analyze his DNA.
"They found a consistent profile that the father's DNA is consistent with that found on the knife sheath," said Podini.
DNA technology is getting more and more sophisticated
In the four decades since DNA profiling was introduced, advances in science and technology have resulted in more accurate analyzes to track down criminals.
For example, tools for analyzing DNA are becoming more sensitive, so that samples from DNA touch with less information, which can still be used by investigators to hunt down and identify suspects.
Technological advances in DNA forensics, along with genealogy sites like 23andMe and Ancestry.com, have helped solve murders that occurred decades ago, including the arrest of the Golden State Killer killer in California in 2018. He was active in the 1970s and 1980s.