The I-Team has late details on the investigation into the Navy Yard mass murder in Washington, including sailors who remember when they were in boot camp with the killer at the Great Lakes Naval Station north of Chicago.
Red flags are piling up as authorities hunt for a motive in the mass murder at Washington's Navy Yard complex. The signals that something was wrong with Aaron Alexis go back even before his days at the Great Lakes Naval Center, when he came into the service, he had already been arrested for gun violence. Defense officials, federal investigators, the shooter's relatives and friends are all trying to recall the red flags they may have missed.
"Very mild mannered and he kept to himself and that was that," said Jason Niehoff, who was in boot camp with Alexis.
Jason Niehoff spent nine weeks in Navy basic training here at Great Lakes, the Navy's only boot camp facility. Niehoof says he knew Aaron Alexis then, in 2007, during the basic training that all navy recruits undergo.
After leaving Great Lakes, during Alexis' three-year military career, according to Navy officials, he was cited at least eight times for misconduct, including insubordination and excessive absences. He was also arrested twice. In 2008, he charged with disorderly conduct, then he was arrested again in 2010 for firing a gun through his apartment ceiling. He left the Navy in 2011.
Alexis recently made contact with two Veterans Administration hospitals. VA officials say he sought help for insomnia, but something else was brewing inside.
"He was very frustrated with the government and how as a veteran he didn't feel like he was getting treated right or fairly," said Kristi Suthamtewakul, friend of Aaron Alexis.
As the I-Team first reported on Tuesday, Alexis made a return visit to the Great Lakes Naval Station north of Chicago a few weeks ago. This summer, out of the Navy, he was a civilian desktop computer troubleshooter working for a military contractor.
After leaving Chicago, Alexis ended up assigned at the Washington Navy Yard, where Monday morning he opened fire on a crowded cafeteria. In a quirk of fate, Alexis' friend from boot camp was working at the Navy Yard.
"I wanted to make sure he was who I thought it was. I recognized his face and name and I had thought that I did know him and I waited a day or two to let it sink in and make sure we were in fact in the same division at boot camp," said Niehoff.
It was the same man and they had been in boot camp together. Niehoff was probably the only person to be with the shooter at the beginning of his military career and the end of his life. Despite what happened, Niehoff says he felt secure working at the Navy Yard and praised those who responded to the tragedy.
The U.S. Veterans Affairs Department said Wednesday that gunman Aaron Alexis visited two VA hospitals late last month for insomnia. But VA officials say Alexis denied having serious mental problems or thoughts of violence.
"Why they didn't get picked up, why they didn't get incorporated into the clearance process, what he was doing, those are all legitimate questions that we're going to be dealing with," said U.S. Secretary of Defense Chuck Hagel.
Pentagon investigators and federal law enforcement said Wednesday afternoon they do not deny there were missed signals that Aaron Alexis was suffering from mental problems. But so far there has been no motive established for Monday's shooting rampage.
One incident, on August 7 at 6 a.m., Alexis called Newport, R.I. police claiming an unidentified person "had sent three people to follow him and keep him awake by talking to him and sending vibrations through his body through a microwave machine."
Newport police say they contacted Navy investigators who determined Alexis was not a threat.
About a month later, he killed 12 people. For the first time, we heard from the mass killer's mother on Wednesday.
"His actions have had a profound and everlasting effect on the families of the victims ? I don't know why he did what he did and I will never be able to ask him why ? Aaron is now in a place where he can no longer do harm to anyone and for that I am glad ? To the families of the victims I am so, so very sorry that this has happened ? My heart is broken," said Cathleen Alexis, gunman's mother.
The Navy Yard is still closed Wednesday, but employees were able to pick up their cars that had been stuck in parking lots since Monday Morning. On Wednesday the Pentagon pledged a full review of security at all its facilities and of the security clearance process.
"Where there are failures, we will correct them. We owe the victims, their families and all our people nothing less," said Hagel.
Among the cryptic clues that authorities are examining this afternoon: two mysterious phrases carved on the stock of the shotgun used by Aaron Alexis. ABC News has learned that he apparently etched into the wood the words: "better off this way," a possible reference to a suicide mission; and "my E-L-F weapon." "E-L-F" can stand for "extremely low frequency" in the tech world. It also is the partial name of a character in a video game that Alexis was known to favor, which may be the more likely explanation.
Newport, R.I. police report on Aaron Alexis