>> and when they looked at the forensic evidence, the prosecutor says it was clear the struggle began inside sarah's bmw. >> there was a significant amount of blood and a large clump of her hair in the door jam. >> it's a frightening discovery, finding hair and blood. >> it is. and the amount of hair that was out -- hanging out of that door jam was significant. >> sarah's bmw had been towed to the police department's impound yard where forensic experts went to work. >> they spent quite a long amount of time going over that car. >> besides blood and hair, something else caught their attention. ...