Most likely, it was suicide. Here are the most obvious alternatives:
- Government sanctioned assassination: possible, but unlikely. Certainly, under sufficiently important conditions, the government is willing to resort to this. It would need to be something like Aaron stumbling across evidence of a 9-11 cover-up as part of his Wkileaks activities. Nothing we already know about would be sufficient reason.
- Non-government murder: possible, but very unlikely. There is no indication that he was in serious conflict with anyone.
- Auto erotic accident: in his case, almost impossible. He would have been aware of the risks and too smart to suffer this.
If it was suicide, then what was the ultimate trigger? Bear in mind that suicide (at least, in modern Western societies) is rarely the result of the single event.
- Acute depression with no particular cause: most probable. It would be interesting to know if his long-standing problems with episodes of depression were being treated, and (if so) how. Drug treatments are usually effective against acute depression, though this varies from person to person and relief of symptoms is usually not immediate, and long term drug use often subject to side effects and reduced effectiveness. Cognitive therapies are usually only effective against mild to moderate depression.
- Legal problems: unlikely as a major cause. I personally believe he would have relished fighting his legal persecution. Any suicide as a reaction to the prospect of a long prison sentence would have needed the case to be much further advanced.
- Blackmail (by the government): very possible. Many people have secrets (often not illegal) that they desperately want to keep from others. Given his involvement with Wikileaks, the government would definitely have tried to blackmail him if they had anything they could use for that purpose.
- Personal relationship problems: possible, but no evidence to support that theory.
Really, there is nothing except supposition to support foul play. Without something concrete to go on, his family and close friends should be left to grieve in peace.
RIP, Aaron. I only know you through your Internet freedom advocacy, but regret your passing.