Washington Navy Yard shooter Aaron Alexis had been receiving mental health treatment, had anger management issues, and told Rhode Island police that he had been hearing voices and was being harassed through microwave mind control. Most people who heard that needed no further explanation for Monday's tragic events. They understood the 12 deaths and eight injuries to be the sad result of severe mental illness, perhaps even paranoid schizophrenia.

But before (and even after) the details of Alexis' difficult past emerged, many people on the fringe had instead opted for a range of conspiracy theories — just as they did in the Sandy Hook massacre, the Aurora, CO movie theatre shooting, and even 9/11. The conflicting reports as to whether the shooter was a civilian or a servicemember, the number of shooters involved, the incorrect identification of the suspect, and a whole host of other unanswered questions were all fodder for conspiracy theorists of varying intensity to take to Twitter, YouTube, discussion boards, blogs, and other online outlets to assert the sometimes absurd and the sometimes plausible.

For some, it was a "false flag," a covert military operation:

I sense another false flag event from in this Navy yard shooting...just a hunch. Who will be blamed? Syria, Iran, Russia, China, Tea Party? — Michael O (@StormSurge2013) September 16, 2013

Navy Yard shooting –> another false flag attempt — Naimah Iman ♔ (@Love_ndReggae) September 16, 2013

For others, the event was premeditated or a hoax, and the media was in on it:

Or it was an attempt by nefarious overlords to distract the public:

Y'all don't get it yet? The war didnt pop off so they hv to distract u with fear and anger with something else ...navy yard/police shooting — Elidi Bey (@ElidiBey) September 16, 2013

Some conspiracists suggest that Alexis was a "targeted individual," or "TI," the term-of-art used by anguished people who believe they're being "gang stalked" by shadowy enemies, often in the government. The elements of Alexis' police report – covert microwave weapons, conspiracies and sleep disturbances – are common elements in gang stalking accounts. (Of course, they're also common elements in schizophrenia.) But even believers in those accounts didn't support Alexis' violent rampage. "Aaron is a murderer. I do not agree on any level with his actions or guns," writes one poster to gang stalking forum. "But this story has more evidence than most pointing to the use of microwave weapons, gang-stalking."

Another writes: "Using Aaron Alexis as an example could look bad, after all he killed 12 people. He had made a choice to keep and use guns. I would hope any real TI would see the danger in keeping a gun. The perps could influence you or even just take over your body, and make you use that gun on someone else, maybe even a loved one."

The microwave weaponry theory would be just as absurd as some of the other conspiracies if the Pentagon hadn't been researching the possibility of using similar voice-projection technology in the past as a nonlethal weapon.

According to one report on the project, such a weapon would create a condition similar to schizophrenia. "Application of the microwave hearing technology could facilitate a private message transmission. It may be useful to provide a disruptive condition to a person not aware of the technology. Not only might it be disruptive to the sense of hearing, it could be psychologically devastating if one suddenly heard ‘voices within one’s head.’"

Of course, the chances of mental illness versus microwave mind control greatly favor the former.