There are so many people to be spoken to in this investigation....Daniel's roommate would obviously have known that he was concerned. The medical records of Kapoor and the psychologist. The Jackie Van Hatten testimony of her seeing HKS give Anna drugs..is amazing. And then if this psychologist used a regression analysis on Anna who knows what she might have tried to stir up. Wonder if HKS and the psychologist were in on this together....? Also, what about the sisters and brothers of Anna's. This certainly turned into such a controlling situation...this is obvious and the police and investigators can't deny this...nor the testimony from Vanhatten.
A lightbulb: It would be interesting to find out if Howard ever worked on any drug cases in the past. While it appears he didn't have any clients of his own, he may have been a research specialist with the firm. That's not unusual.
Maybe that's what's hidden in his past. He had to submit his DNA because of possible contamination on a case he worked on and it's in a database.