In the Smoking Gun article linked from Drudge, he claimed he'd been cooking, his hands were greasy, and the gun slipped while he was cleaning it. The article went on to say:
"The woman, whose name is not listed in a Fort Worth Police Department report, said that she was 'terrified' of Alexis, who had previously confronted her about making too much noise. The woman, who was 'visibly shaken up' when questioned by police, said that she believed the shooting was 'intentional.'”
It also said: "Asked why he did not notify police or check on the welfare of his upstairs neighbor, Alexis said that he 'didn’t think it went all the way through since he couldn’t see any light through the hole.' Additionally, 'In regards to the noise he said he thought that people would just think it was a firecracker.'”
As well: "In early-July [no year given], a male roommate of Alexis’s called Fort Worth cops to report his suspicion that Alexis “put unknown substance in gas tank to damage vehicle,” according to a July 5 report."
And: "Alexis was arrested for disorderly conduct in August 2008 in DeKalb County, Georgia. He was released from custody after posting $364 bond (and posing for a booking photo). The details and disposition of the misdemeanor case could not be obtained."
Looks like the guy has had a series of incidents over the years.
Probably had issues as a Sailor as well, NJP and such. I know AEs are required to have secret clearances. If they rack up problems (legal, financial, etc.) in their personal lives, they can lose their clearance and their rate. Sometimes the Navy will find a different rate for Sailors who lose their clearance. Most often, they show them the door and in January '11, the Navy was kicking Sailors out left and right as part of their "force shaping" (i.e. "downsizing") policies. This is probably what happened to Petty Officer Alexis.
What may be surprising to some, it isn't at all unusual for the Navy to kick Sailors out and then turn around and rehire them as civilian contractors. I've seen this happen many times.