>> reporter: but, they wondered, did she help cover it up? it's a serious business, covering for a crime that awful. but chandy had a card to play. she agreed to testify. >> members and alternate members of the jury -- >> reporter: and in june 2017, john creech went on trial. on the face of it, it looked like a solid case. the phone evidence, the coverup, the truly appalling crime scene in gavin's car. but did it add up to first degree murder? gavin smith had been dead five years. >> he was killed in his mercedes-benz in an act of almost stunning brutality by the defendant john creech who's sitting here in the courtroom. this became gavin smith's tomb. >> reporter: but what happened wasn't merely an outburst of rage, said prosecutor bobby grace. no, he said, creech had been plotting for two years ever since he found out about chandy