. >> reporter: but frances' defense attorneys, leigh cutter and jean brown, said investigators made atake when they bought into the story of bonnie contreras. >> everyone got their information from one person at the scene. and that's bonnie. and bonnie lied her ass off. >> reporter: defense accident reconstructionist charles ruble said there was no physical evidence to back up bonnie's claims that frances had hit her over and over again. no evidence, he said, the suvs had even touched. >> not even once. >> reporter: and remember how bonnie said her purse flew forward off the seat when frances hit her? >> this is her purse in her car. i get hit from the rear. where's my purse go? it doesn't dump in the front. that's simple physics. >> reporter: in fact, he said, the purse falling forward supports frances' claims that bonnie was repeatedly slamming on her brakes. >> she does a sudden brake, and she's moving like this. then the purse would go into the floorboard. bonnie contreras is not telling the truth. >> reporter: what's more, both defense and prosecution agreed bonnie was wrong abou