. >> i'm obviously going to take a few notes, obvus so don't let that bother you. >> reporter: the interviewer withheld details about the crime scene. a standard investigative tactic to see if a subject knows more than they should. he even threw out a theory that wasn't true -- murder/suicide. >> one of the things we have to look at is as to whether or not that one of them would've injured the other and then maybe themselves. >> reporter: jessica seemed to go with it. >> do you think that's a possibility? has been super depressed and has made comments. and my mom called the doctor's office, and i told her if he did -- if he said something stupid before -- again, that she needed to call the police. like get the [ bleep ] away from him and call the police. >> reporter: and as they continued talking, police had another reason to be suspicious of the daughter. she'd driven five hours to check on her parents then didn't go inside the house. wouldn't you wonder why she would do that? >> yes. people sometimes that commit a crime or know a crime that's don't want to see the bodies in there so they cal