Navy Yard shooting gunman's mother Cathleen Alexis "so, so very sorry"
Updated at 1:46 p.m. ET
NEW YORK The mother of the man who killed 12 people at the Washington Navy Yard says she is "so, so very sorry that this has happened."
Cathleen Alexis said Wednesday in New York City that she does not know why her son, Aaron, did what he did and she will never be able to ask him.
The mother read a statement at her home in Brooklyn.
"Aaron is now in a place where he can no longer do harm to anyone, and for that I am glad," she said.
She concluded, "My heart is broken."
She did not want to appear on camera and did not take questions from a reporter.
Thirty-four-year-old Aaron Alexis opened fire at the Navy Yard on Monday before he was killed in a shootout with police.
Authorities say he had been suffering a host of serious mental problems including paranoia and a sleep disorder.
The Navy was told by authorities in Rhode Island last month of an incident in which he complained that he was hearing voices, according to a police report on the incident. It is unclear whether the Navy followed up.
At a Wednesday morning news conference, Defense Secretary Chuck Hagel announced a review of security and access procedures at U.S. defense installations around the world and acknowledged there were "red flags" regarding Alexis' past.
"Obviously, when you go back in hindsight and look at all of this, there were some red flags," said Hagel. "Of course there were. And should we have picked them up? Why didn't we? How could we? All those questions need to be answered."
In August, Alexis was agitated when police paid him a visit at the Marriott hotel he had checked into in Newport, R.I.
Local law enforcement had received a harassment complaint from someone in the hotel, and when they tracked down the source of the complaint, Alexis, the police wrote in their report of the incident that he complained about an "unknown party" of people he had never seen. Alexis said these people had been keeping him awake by "sending vibrations into his body" by "using some sort of microwave machine."
While the motive in the Navy Yard massacre is still unclear, a pattern of agitated and unsteady behavior has emerged in the recent history of the suspected shooter. Officials say they're fairly certain the 34-year-old former Navy reservist had no connections to terrorism.
Alexis told Newport police in August the unknown party following him around had been sending voices through the walls and ceiling. In their report, police said they tried to find out what the voices were saying, but Alexis wouldn't elaborate. Before parting, police claim Alexis said "he does not have a history of mental illness in his family and that he has never had any sort of mental episode."
Police also said in the report that Alexis told them he had checked out of two other hotels to try to escape the voices before checking into the Marriott.
Newport Police Sgt. Frank Rosa says in the report that he informed the Navy of the Marriott incident.
"Based on the Naval base implications," Rosa wrote, "and the claim that the involved subject ... was 'hearing voices,' I made contact with on duty Naval Station Police. I advised of the report and the claims."
Rose added that Navy authorities said they would follow up to determine if Alexis was indeed a Navy base contractor.
A look at Alexis' prior arrest record indicates that he has a history of mental health issues.
On June 3, 2004, Alexis was arrested in Seattle for shooting out the tires of another man's car on May 6 in what Alexis told police was an anger-fueled "blackout." It appeared Alexis may have been angry with construction workers who were using parking spaces in his neighborhood.
On Sept. 4, 2010, Alexis was arrested for allegedly firing a gun inside his Texas apartment because he had been angry about his downstairs neighbor making too much noise. At the time he was a Navy reservist stationed in Fort Worth.
Officials say Alexis also had bouts of insubordination, disorderly conduct and being absent from work without authorization during his four years as a full-time reservist. He frequently complained about discrimination, and officials say his behavior led to an early but honorable discharge in 2011.
When he left the Navy reserves, he managed to keep his security clearance upon becoming a military contractor because his incidents with police never rose to the level of raising an alarm about him being mentally unfit. Additionally, his arrests never gave cause to bar him from buying a firearm, including the shotgun officials say he bought recently in Virginia to carry out the Navy Yard massacre.
- Security scrutinized, motive sought in wake of deadly rampage
- Navy Yard employee helps visually impaired co-worker escape
- D.C. shooting victims included Navy veteran, mother of two
At the time of the rampage, Alexis was an employee with a Defense Department subcontractor on a Navy-Marine Corps computer project, authorities told The Associated Press. Alexis had access to the Navy Yard via a valid pass.
The roots of Alexis' issues are still being examined, but after his 2004 arrest in Seattle, both Alexis' father and Alexis himself told police he had been present during "the tragic events of September 11, 2001" and that they had disturbed him. His father told police he suffered from post-traumatic stress disorder and that his mental issues stretch back at least a decade.
After the Newport, R.I., run-in with police August, Alexissought treatment for mental health issues from the Department of Veterans Affairs, officials say.
Until recently, Alexis lived in Fort Worth at the home of Melinda Downs, reports CBS News correspondent Bob Orr. She said Alexis suffered from PTSD and insomnia. She told reporters he loved the military and showed no signs of violence.
"It's like Dr. Jekyll and Mr. Hyde, who was this guy?" Downs said. "The guy that I knew was so honorable. It breaks my heart."