The family of the Stamford, Conn., woman who drove her car into a barricade outside the White House before leading police on a chase to the U.S. Capitol told law enforcement that she had been diagnosed with psychosis and wasn't always fully aware of where she was, sources said.
Law enforcement officials have continued to interview relatives and friends of Miriam Carey, 34, and are developing a fuller a picture of her mental state, reported WNBC's Jon Dienst.
Carey was struggling with post-partum depression and sometimes wandered with her baby daughter in her arms, and she had also been hospitalized, family members told authorities.
Recently, she topped taking her anti-depressants, family members told law enforcement, and authorities found indications that Carey believed the president was communicating with her.
"We are seeing serious degradation in her mental health, certainly within the last 10 months, since December, ups and downs," said a federal official, who had been briefed about the investigation but was not authorized to discuss it publicly and spoke to the Associated Press on condition of anonymity. "Our working theory is her mental health was a significant driver in her unexpected presence in D.C. yesterday."
The woman had made delusional "expressions about the president in the past" and believed President Barack Obama was communicating to her, the official said.
"Those communications were, of course, in her head," the official said, adding that concerns about her mental health were reported in the last year to Stamford police.
Miriam Carey's boyfriend contacted police in December saying he feared for the safety of their child, who was 4 months old at the time, according to a law enforcement source involved in the investigation. The boyfriend said the woman was acting delusional, claiming the president had placed Stamford under lockdown and that her house was under electronic surveillance, the source said.
He told police that she was suffering from post-partum depression, was having trouble sleeping and was on medication. Carey underwent a mental health evaluation, said the source, who added that the boyfriend has been question by federal authorities about Thursday's events, NBC News' Pete Williams reported.
The source told said Carey left a letter addressed to the boyfriend at her apartment and that it appeared to contain white powder. The letter is being tested for hazardous substances.
Carey's mother, Idella Carey, told ABC News her daughter began suffering from post-partum depression after having her daughter last August.
"A few months later, she got sick,'' she said. "She was depressed... She was hospitalized.''
Idella Carey said her daughter had "no history of violence'' and she didn't know why she was in Washington on Thursday. She said she thought Carey was taking her child to a doctor's appointment in Connecticut.
Idella Carey also said that her daughter had been in Connecticut the day before her shooting and had told her she was going to a Michael's store to buy some arts and craft supplies. Investigators believe that she drove straight to the nation's capital and that the violence unfolded immediately upon her arrival.
The incident began after 2 p.m. Thursday at the White House gates at 15th and E streets NW. Police say Carey, with her 1-year-old daughter in the backseat, attempted to ram a temporary security barrier outside the White House with her car, then struck a Secret Service uniformed division officer. She then fled the scene, leading police on a chase.
Video submitted to NBC Washington by AlhurraTV shows the woman's car surrounded by officers with their guns drawn in Garfield Circle, just outside the Capitol. Carey bashes into a barricade, backs up and then drives away. Officers fired nine shots, sources told NBC Washington's Pat Collins.
Carey then led Secret Service and Capitol Police to Constitution Avenue and 2nd Street NE, where she saw barriers and attempted a U-turn on Constitution, sources said. Officers fired another 17 shots, and Carey hit the accelerator and crashed into a guard shack.
Officers approached the car, saw Carey was dead and discovered her daughter in the car.
Initial reports said Carey had exited her vehicle and fired shots, but News4 later learned Carey was not armed and did not fire any shots. D.C. Police Chief Cathy Lanier said Capitol Police and Secret Service fired their weapons.
Carey was shot and killed at the scene.
One of her sisters will travel to D.C. to identify Carey's body. The family will ask for temporary custody of Carey's daughter until longer-term decisions can be made.
Carey was licensed as a dental hygienist and previously worked at Advanced Periodontics in Hamden, Conn., from 2011 to August 2012.
Her former employer, Dr. Barry Weiss, describes Carey as hot-tempered and head strong but says he never imagined she could be capable of violence.
"She was an average employee. We started out with a pleasant relationship in the office. We had a few incidents... and some hot-tempered situations, but for the most part she was an average employee," Weiss said.
The FBI and Secret Service contacted Weiss on Thursday and he said he was completely stunned by the news.
"Nothing would have led us to think she would have done this," Weiss said.
Carey was fired from the dental office after clients began complaining about her.
"Really, we just had a lot of complaints about her from patients that she was a dental hygienist and rough. We just decided that for the betterment of our patients, we needed to make a change and let her go," Weiss said.
He said he never believed Carey was violent or out of control.
"Nothing in her behavior would have led us to think this would have happened," he said.
Weiss said that Carey came from a large family and was close to her siblings.
Like everyone else, he wants to know why this incident happened.
Late Thursday afternoon, the Stamford Bomb Squad arrived at Carey's Connecticut condo, where Carey lived for the past six years, and removed evidence, including a computer.
Authorities said they did not find anything dangerous or hazardous in the residence.
Members of the FBI joined Stamford police and fire officials at the scene, and authorities blocked off Washington Boulevard and Bridge Street on Thursday night. All 50 apartments were evacuated.
Residents were not allowed inside as police waited on a search warrant, and the Red Cross was helping residents find other places to stay.
The search ended Friday morning, and residents were allowed back inside their homes.
Police said there appeared to be no direct link to terrorism. Capitol Police Chief Kim Dine called it an "isolated, singular matter.''
Two officers were wounded in the incident: A 23-year veteran of the Capitol police, who has been treated and released from the hospital, and a member of the Special Services, who officials say is also in good condition.
The shooting comes two weeks after a mentally disturbed employee terrorized the Navy Yard with a shotgun, leaving 13 people dead including the gunman.
Before the disruption, lawmakers had been trying to find common ground to end a government shutdown. The House had just finished approving legislation aimed at partly lifting the government shutdown by paying National Guard and Reserve members.
Capitol Police on the plaza around the Capitol said they were working without pay as the result of the shutdown. A spokesman for House Majority Leader Eric Cantor said a bill to pay them was under consideration.