Miriam Carey, 34, was fatally shot, authorities said, after she tried to drive past a barricade near the White House and struck a Secret Service officer. Ms. Carey drove off, rammed at least one car along the way, and finally stopped blocks from the Capitol, which was briefly locked down. One police officer was injured during the pursuit.
Even as Ms. Carey's history is investigated, many of the details surrounding the response by law enforcement officers remained unanswered, including the sequence of events in the moments before she was shot. After she was shot, no firearm was found on her or in her car.
A 1-year-old in the car was unharmed and was in protective custody on Friday.
Soon after the chase ended and Ms. Carey was identified, dozens of law enforcement officers went to her apartment in Stamford, Conn.
After obtaining a search warrant, they found at least two prescription medications for mental health issues — one that is commonly used to treat schizophrenia and bipolar disorder, and another that is an antidepressant, according to one law enforcement official briefed on the investigation.
They also found a laptop computer, which may provide some insight into her motivations, as the police begin the painstaking work of trying to reconstruct what happened in the days and weeks leading up to Thursday's deadly encounter with the police.
The authorities have determined that she drove to Washington that morning, but they were still unclear why, according to the law enforcement official.
There were conflicting reports about Ms. Carey's mental health — with friends and associates offering a range of explanations, including postpartum depression, trauma from a head injury and a longer-term illness. A lawyer for Ms. Carey's family, Eric Sanders, was not immediately available for comment but his office said he would be issuing a statement later Friday.
The authorities cautioned that it was still an active investigation and they would not comment on any specific medical diagnosis she may have received over the years.
The law enforcement official, who requested anonymity in order to speak about the case, said investigators were still trying to figure out how much credibility to lend to reports from associates of Ms. Carey that she was delusional and believed she was being stalked by President Obama.
Her mother, Idella Carey, told ABC News that her daughter was suffering from postpartum depression and had a history of mental illness.
The network reported that in December, Ms. Carey was taken to Stamford Hospital after a dispute with her boyfriend and later told a social worker that she was being treated at a mental health facility.
A spokeswoman for the Connecticut department of mental health said she could not say whether the department had had any contact with Ms. Carey or referrals from law enforcement agencies about her.
Ms. Carey, who worked for years as a dental hygienist, was the second youngest in a family of five daughters who grew up in an apartment building on Stanley Avenue in East New York, Brooklyn. Her sister Franchette, who still lives in the apartment with their mother, said she saw Ms. Carey this week and she seemed fine.
To many who knew her, nothing appeared outwardly wrong. But others said there were warning signs going back years.
A former boss, Dr. Barry J. Weiss, who employed Ms. Carey at his periodontics practice in Hamden, Conn., for 15 months, said he and his partner fired her in August 2012. He would not go into detail but said she had trouble getting along with some of the employees in the small practice.
Majestic Steele, a family friend, said that a few years ago he saw her standing outside her mother's apartment building, clutching a leather-bound Bible and yelling at the sky.
"She was saying, 'Help me' and 'I need you,' and she was quoting Scripture," Mr. Steele said. "The way she was speaking it sounded like she was in trouble, she wanted help."
Reporting was contributed by Kristin Hussey in Stamford, Conn., and William K. Rashbaum and Nate Schweber in New York. Sheelagh McNeill contributed research.
