I think, based on the info he had approached a PI to help him with his mother, because he thought she was being taken advantage of by HKS and others, that he said something to the effect to Stern on the drive from the airport and Stern offed him to shut him up. Remember, there is the unexplained bruises on Daniel that maybe we'll hear more about at the inquest next week.
They were called abrasions in the autopsy, not necessarily any bruising present.
They were on the front and back of the left and right pelvis area and did not happen during revival or resuscitation efforts.
That means they are small scrapes or scratches and if they bled some tiny amount, that meant they were ante-mortem.
I've thought about this a lot and my opinion, which could always change, is that it might have been something that happened when *someone* went through his jeans pockets, perhaps too roughly.
In order to do that, he would have had to have been already unconscious or half-conscious.
We heard about two pills that were found in the bed where either he or HKS had been; we heard about HKS finding pills in Daniel's jeans pockets, but it was implied that he did that back at the house, in Daniel's other jeans (he wasn't in them, IOW) - and we also heard on the tab TV show the other day (I did, anyway) when Jack Harding, the PI, appeared, that Harding's business card - which they showed close-up, on-screen - was found in Daniel's jeans pocket.
Anna did confide in a couple people that she felt she was in danger from Howard. We know Shelley was one of them, maybe she even confided this to Larry Birkhead. And maybe Birkhead told Daniel. Or maybe Daniel himself just felt she was in danger because he knew what things were like in CA. And the move to the Bahamas probably scared him even more because he wasn't there to protect his mother. He was young so i'm thinking someone advised him to get a PI. And what if this news got back to HKS thru some mutual acquaintance/friend?