NEW HAVEN - Forensic science could become crucial as police investigate the killings of a couple from Easton.

Kyle Navin is accused of murdering both his parents for profit, then dumping their bodies in Weston.

Criminologists learn how to analyze crime scenes at the forensics lab at the University of New Haven. At the lab, they examine the unique markings on bullets to identify and match the bullet to the weapon it was fired from.

Just like people have fingerprints, forensic experts say every gun leaves its own "ballistic" fingerprint on a bullet. Experts say that could be a key piece of evidence in tying Navin to his parents' murders.

Under a microscope, investigators can use bullet markings to match the ones found with the Navins' remains to guns Kyle owns.

Investigators will also be examining the Navins' remains for signs of a physical struggle.

"Depending on the decomposition of the tissue, they can look and see if there were bruises, scratches, cuts, marks - that kind of thing," says Peter Massey, of the Henry Lee College of Criminal Justice.

The evidence in the Navin case is still under investigation.

Ballistics tests can only connect the guns Kyle Navin owns to the killings. Police will still have to prove Navin is the one who actually fired the fatal shots.