Law enforcement authorities still don't know why a Connecticut woman tried to breach a barrier at the White House, setting off a high-speed car chase that put the Capitol on lockdown and ended with her being shot dead by police.

Officials identified the female driver as 34-year-old Miriam Carey, of Stamford, Conn. She was traveling with her 1-year-old daughter who avoided serious injury and was in protective custody late Thursday.

The incident began at about 2:30 p.m. at the White House gates at 15th and E streets NW. Police say Carey had 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.

Carey then led Secret Service and Capitol Police on a chase to 2nd Street and Maryland Avenue NE, where she crashed into another barricade, sources told NBC Washington's Jackie Bensen.

Initial reports said Carey had exited her vehicle and fired shots -- sources now tell News4 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.

News4 confirmed an 18-month-old infant was in Carey's car at the time, and is expected to be okay.

In the midst of the incident, a 23-year veteran of Capitol Police crashed his car. He was hospitalized and later released from MedStar Washington Hospital Center.

The Secret Service division officer struck by the woman while she was driving is also expected to be okay.

Lanier confirmed no officers were struck by gunfire during the shooting.

The U.S. Capitol was placed on lockdown for about an hour, and police officials said they will review their response to security breaches.

The shooting comes on day three of the first government shutdown in 17 years, a tense standoff between the House and the Senate over the federal budget and President Barack Obama's Affordable Care Act. Both sides have accused the other of refusing to negotiate, and tens of thousands of federal workers have been furloughed.

However, Carey's motives remain unknown. The incident appeared to be isolated and was not related to terrorism, said U.S. Capitol Police Chief Kim Dine.

Carey's mother, Idella Carey, says her daughter began suffering from post-partum depression after having her daughter, Erica, last August.

Idella Carey says her daughter had "no history of violence'' and she didn't know why she was in Washington, D.C.

Carey had worked as a dental hygienist in Hamden, Conn. Her former boss said she was very "headstrong," but he said nothing about her would have led him to think something "like this" would happen.

He said Carey had fallen down stairs and suffered head trauma. After returning to work from that injury, he said Carey had a "chip on her shoulder" and was too rough with some patients. She was fired in 2012.

Late Thursday evening, police prepped to search Carey's Stamford apartment.