The 34-year-old Connecticut woman who was shot and killed by police after a harrowing high-speed chase from the White House to Capitol Hill suffered from post-partum depression, her mother told ABC News.

Miriam Carey, a dental hygienist from Stamford, Conn., was identified as the driver of the black luxury sedan that first rammed a barrier at the White House, then sped to Capitol Hill, defying attempts by armed police to stop her Thursday afternoon. She was shot and killed fleeing her car near the Hart Senate Office Building

Afterward, police discovered Carey's 1-year-old daughter was in the backseat of her black Infiniti throughout the ordeal. The child, who was not injured, was taken to a hospital for a precaution and placed in protective custody.

Authorities who descended on Carey's condo in Stamford have not determined a motive for her bizarre behavior through downtown Washington, D.C.

Her mother, Idella Carey, told ABC News on Thursday night that her daughter began suffering from post-partum depression after giving birth to her daughter, Erica, 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 that she had no idea why she was in Washington on Thursday.

The New York Daily News quoted Carey's former boss, dentist Brian Evans, as saying that she "fell down some stairs and she had a pretty significant head injury" in recent years.

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Evans also said that Carey, who was let go last year, had a temper and became incensed over being told to quit parking in a handicapped spot at the medical building in Hamden, Conn., where she worked. That created friction between them, he said.

Carey's former employer in Connecticut, dentist Barry Weiss, told NBC Connecticut that she was a bit "headstrong" on a few occasions but was otherwise "an average employee."

Weiss also that said Carey "could be a bit rough," and after complaints from patients, was fired in August 2012.

"Nothing would have led us to think she would have done this," said Weiss.

Another former boss, dentist Steven Oken, for whom she worked eight years, described Carey as a "non-political person" who was "always happy."

Court records also show that Carey was sued last year by her condo association for failure to pay fees since 2010 on the Stamford home she owned since 2009. The lawsuit, involving $1,759 plus collection costs, was settled in February, the Associated Press reports.

U.S. Capitol Police Chief Kim Dine said the incident "appears to be an isolated, singular matter, with, at this point, no nexus to terrorism."

Two federal officials, who were not authorized to comment publicly, told USA TODAY that all shots were fired by law enforcement officers. One official said no gun was recovered from her car.

"This does not appear to be in any way an accident," Metropolitan Police Chief Cathy Lanier said Thursday. She noted that Carey twice tried to breach security barriers and struck a uniformed Secret Service officer near the White House.

The chaotic events began at 2:12 p.m. ET when the driver rammed a temporary barrier at 15th and E Streets NW, hitting the officer, said Secret Service chief Ed Donovan. Other Secret Service officers chased the woman east on Pennsylvania Avenue but did not shoot.

Lanier said Capitol Police officers pursued the speeding car eastbound and tried to stop it in Garfield Circle, just west of the Capitol lawn. A 23-year-veteran officer suffered non-life-threatening injuries when he crashed into a barrier.

Police had the woman's car surrounded but she escaped, ramming a Secret Service vehicle as she fled. Lanier said police then fired their first shots at the suspect.

The driver made her way onto Constitution Avenue before eventually stopping in the 100 blocks of Maryland Avenue NE, near the Hart Senate Office Building.

Contributing: The Associated Press