The FBI agent said it's likely someone who had worked on the house/in the house and knew what she had. Most people are very kind to workers, offering a cold drink, or bathroom use. Gives them a chance to case the house while the homeowner is unsuspecting. They went to rob her, and she woke up and that's when the original plan went sideways. He thinks it was a moronic split decision to take her and hatch the kidnapping plan. They didn't want to leave a witness, but maybe weren't prepared to murder her.
As far as the AG and SIL he said (starting at 23:00m approx). He said the focus on her house has to do with gathering evidence (digital info) about help AG hired for Nancy, all the electronics would be on Annie's stuff because she would have been the appointment maker. He also said most people who are accused "lawyer up" and shut up. They've been completely cooperative. Elizabeth Smart's dad was a suspect, they look at and rule out the closest, then rule out. Deep dive on Tomasso, he's a long time 6th grade teacher in the sciences, no criminal record and he said, "If they were hard up on money there would be a hell of a lot easier ways to get it, like robbing a bank than to do this". The family doesn't fit the profile, he said.