you're homicidal. that's a real quick switch. >> that gave the detectives a powerful reason to reinterview bob but fearing he would lawyer up, they lured him back to the frisco pd by saying they had information for him on anna's estate. >> thanks for coming out, bob, we appreciate it. >> once inside the cramped interview room, the investigators immediately changed the subject to bob's shaky alibi from the day of the murder. turns out, his roommate could not vouch for bob or his time line as bob said he would. >> i know it's been a couple weeks, but if you can remember -- >> i'm distraught. >> i'm sorey. but that is vague. >> i'm not trying to be vague. i don't have details for you. there is no details. i was sitting there watching tv. okay, 2:00, i'm watching tv.