a camera was rolling as prosecutor fran humphries began his case. >> so this is purely motive evidence which establishes a motive for richard gagnon to end the lives of these two people. >> reporter: as humphries recalls, the case against rick was always motivation strong, evidence weak. charlie parker's blood on a shoe when you came right down to it. even so, humphries told the court the blood put rick at the murder scene. but he had a story for it, didn't he? >> he did. it didn't hold water. >> reporter: humphries recited rick's version of how blood got on his shoe. how he'd gone into the parker some time after crime scene techs had finished up. was the window leading in to the bathroom where big charlie had died and noticed the blood. >> reporter: rick said he worried bambi, pacing outside, might look in the window and freak out all over again. >> he went in and stepped through the bathroom and closed the blind. >> reporter: and whoops, i stepped in the blood. >> yeah. up? >> no, because they were already closed. >> reporter: that was the gotcha. this crime scene photo, said the pro

. >> reporter: but to prosecutor fran humphries, it made perfect >> the motive is unavoidable in this case. bambi needed her stepfather and mother dead so she could get her property back. >> reporter: property valued at north of a million dollars. the classic question that people in your line of work pose is, well, who benefited? >> bambi. >> reporter: as for bambi's boyfriend rick, humphreys believed bambi persuaded him to help her carry out the murderous deed. gagnon is her puppet, the way you see it? he's carrying out her orders? >> i think he's been her puppet from the beginning. >> reporter: what did you think? >> i don't know. i was scared to death. >> reporter: in cahoots with your girlfriend balmby. that's the theory, right? >> yeah. i guess so. >> reporter: but both rick and bambi said the prosecutor had it all wrong. they insisted they would never do anything to harm diane or charlie. and bambi downplayed the family drama over the land, despite calling it a feud during her interrogation. >> she wants the land. ever. it was given to me by my daddy to begin with. and even thou