The Dallas News identifies the shooter as a Naval reserve petty officer. One close friend said he was an "even-keeled" Buddhist who spoke Thai, while a former neighbor said he scared her by shooting through a ceiling after he complained about the noise they made:

Alexis enlisted in the Navy in 2007 and left the service in 2011. He was at the Fleet Logistics Support Squadron in Fort Worth. That squadron is located at the Naval Air Station in Fort Worth.
He was a petty officer, 3rd class. He worked on the various electrical engineering systems of aviation equipment. He had no overseas or combat duty.

Alexis’ former roommate said he owned a handgun and “can be tough,” but that he wasn’t a violent person. Oui Suthamtewakul said he met Alexis at a Buddhist temple and lived with him for three years in several different locations.

"We became best friends," he said. "He's like my big brother."

Alexis would help out at Suthamtewakul's Thai restaurant, Happy Bowl, on White Settlement Road in Fort Worth. He also became fluent in Thai from watching Thai dramas and talking to people. He also traveled to Thailand at one point.

Suthamtewakul got married a few months ago, and Alexis moved out. He said Alexis, who had been unemployed, got a job working for a Navy subcontractor. He was also in the Reserves.

But one of Alexis’ former neighbors once told police that Alexis scared her.
Fort Worth police arrested Alexis in 2010 after he shot through the floor of his upstairs neighbors’ apartment. Alexis told police that he was cleaning his gun while cooking and that it accidentally went off. The neighbor told police she believed the 2010 shooting was intentional.

According to a police report, Alexis complained often that the neighbor made too much noise and confronted her in the parking lot several days before the shooting. When police first went to Alexis’ apartment, he didn’t answer their knocks. After parademics arrived, he came to the door and told police the shooting was an accident.

Police arrested Alexis, but the Tarrant County District Attorney’s office decided not to prosecute.

“After reviewing the facts presented by he police department, it was determined that the elements constituting recklessness under Texas law were not present and a case was not filed,” district attorney spokeswoman Melody McDonald said in a prepared statement.

According to Tarrant County court records, Alexis was evicted from the apartment weeks later. A woman who works for the apartment complex’s management company acknowledged the 2010 shooting incident, but declined to comment further.

I've been watching MSNBC, FOX and CNN, and reports about the shooting are coming out fast and furious. Although some details are not tracking, most reports are putting the number of casualties to be at least twelve victims so far and many others wounded.

Law enforcement officials identified the deceased gunman in Monday's shooting at the Washington Navy Yard as Aaron Alexis, a man in his 30s from Texas.

The shooter, who was killed by police during a gun battle some two hours after the initial shootings, was a government civilian contractor new to the D.C. area, said a law enforcement official speaking on condition of anonymity to discuss the investigation.

At least 12 people, including a shooter, have been confirmed dead in a rampage at the Washington Navy Yard, District of Columbia Mayor Vincent Gray said Monday. Officials continue to search for two “potential” additional suspects in the case, D.C. Police Chief Cathy Lanier said, although other officials say the evidence indicates only one gunman was involved.

Officials said they still do not know a motive for the shooting but that they do “not have any evidence to think” that it was related to terrorism.

Reports have said there may be more than one shooter and they are still persisting:

"We potentially have two other shooters that we have not located,” Lanier said in a brief news conference outside the gates to the sprawling base.

Lanier confirmed that one shooter had been killed, but said that police were still searching for a white male last seen about 8:35 Monday morning wearing khaki military-style clothes and a beret and carrying a handgun, and a black male about 50 years old, wearing a military-style olive, drab uniform who may have been carrying a rifle.

Lanier said though the men were wearing military-style clothes, they may not actually be members of the military. The investigation is still “very active,” she added, asking residents to stay out of the area and in their homes while police search the area.

Gray called the shooting a “horrific tragedy.”

I heard Alex Wagner mention that since Obama was elected into office in 2009, there's been a huge rise in mass shooting in America. When Dave and I wrote our book, Over The Cliff, we predicted a huge rise in violence due to right wing extremism and I'm sad to say that we are being proven right at this time.