NEW YORK (CBSNewYork/AP) – The Connecticut woman shot to death by police after she tried to drive through barricades outside the White House held the delusional belief that the president was communicating with her, a federal law enforcement official said Friday.

Authorities said Miriam Carey, 34, of Stamford set off a high-speed car chase that put the Capitol on lockdown Thursday and caused panic in a city where a gunman killed 12 people two weeks ago.

Carey was traveling with her 1-year-old daughter who avoided serious injury and was taken into protective custody.

The chain of events began Thursday when Carey sped onto a driveway leading to the White House, over a set of barricades.

When she couldn’t get through a second barrier, she spun the car in the opposite direction and then sped down Pennsylvania Avenue. Then the chase began.

She was surrounded by police cars, but drove off, careening around a traffic circle and past the north side of the Capitol. Video shot by a TV cameraman showed police pointing firearms at her car before she rammed a Secret Service vehicle and continued driving.

“When I heard gunfire, about five or six rounds, that’s when my wife and I just dropped to the ground,” said witness Edmund Ofori-Attah.

Police shot and killed Carey a block away.

One Secret Service member and a 23-year veteran of the Capitol Police were injured. Officials said they are in good condition and expected to recover.

Authorities are also looking at police tactics in the incident. Why, for instance, when they had Carey surrounded did they not simply shoot out her car tires?

“Those five officers are carrying handguns. Those handguns are gonna be ineffective on modern radial tires. They are wrapped like Kevlar, like a bulletproof vest, so the bullets would just bounce off and be dangerous and be ineffective,” police tactics expert Tom Fuentes told CBS 2′s Dick Brennan.

And why did officers open fire on Carey, when she was unarmed?

“You gotta remember it’s the White House and the Capitol and in an officer’s mind, especially when there’s a vehicle involved, that it seems to be getting the barricades of a building that it could be a terror attack, or a car bomb or something else,” CBS News senior correspondent John Miller said.

– Who Is Miriam Carey? –

Family members were shocked to heard that Carey was involved in the frightening scene that unfolded in Washington D.C.

“I didn’t know she was in D.C. I was on my way to work and the call was very sudden. I was told and I figured out just like everyone else on the news,” her sister said.

Her sisters spoke with CNN and said that she was struggling with post-partum depression and psychosis.

“People need to see she was more than the suspect that was driving the car,” another sister said, “She worked closely with her doctor to get off the medication and get the counseling she needed with that diagnosis.”

Carey had an encounter with Stamford police in December 2012 that resulted in her being taken for a  mental health evaluation, law enforcement sources told CBS News’ Bob Orr.

Carey said she believed that President Obama had placed her and her residence under some kind of electronic surveillance, according to sources. She told police she was a prophet and said that Obama would place the entire city of Stamford under a “lockdown,” sources told Orr.

Carey was not arrested or charged with any crime, and so far there is no evidence that she ever made any kind of threat against Obama, sources told Orr.

Sources said local police did not notify the Secret Service of their encounter with Carey and her name was not in the Secret Service system prior to Thursday’s incident, sources said.

Carey’s mother, Idella Carey, told ABC News Thursday night her daughter began suffering from postpartum depression after giving birth to her daughter last August.

“A few months later, she got sick,” she said. “She was depressed. She was hospitalized.”

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 daughter to a doctor’s appointment in Connecticut.

Shortly after the incident, federal authorities executed a search warrant at Miriam Carey’s Stamford home, and police officers cordoned off the complex and the surrounding neighborhood.

“Federal and State Authorities have worked collaboratively with local Stamford authorities to gather information at the scene of 114 Woodside Green,” Stamford Mayor Michael Pavia said Thursday.

“Early this morning, upon completion of the on-scene investigation, residents were able to return to their occupancies. All inquiries concerning the investigation must be directed to the Federal Bureau of Investigation (FBI) in New Haven, Conn.”

Police Chief Jonathan Fontneau said evidence seized from the two-bedroom home included a computer, WCBS 880′s Paul Murnane reported.

“We went in and out of the apartment,” he said. “We brought our bomb team tech in, we secured it with the robots, we made sure that it was safe and then we made entry and then actually physically went through and secured evidence.”

Fontneau said no hazardous material was found and testing on the air was negative. He said the nothing inside the home appeared to be out of the ordinary.

Carey had been sued by her condominium association for failure to pay fees, court records show. A lawsuit settled in February alleged that she owed the association $1,759 in addition to collection costs, and indicates that she took out a mortgage on her condo in the amount of $237,616.

PHOTOS: U.S. Capitol Placed On Lockdown

Thursday’s deadly drama may have been fueled by delusions, CBS 2′s Weijia Jiang reported.

“Stamford police had a couple of contacts with her involving what they described as delusional statements, that President Obama was listening to her and communicating and so on”, said CBS News’ Miller.  ”So they’re going back over those reports to see if any of that can enlighten them to what was her mental state.”

Dr. Brian Evans, a periodontist in Hamden, Conn., said Carey worked as a hygienist in his office for about two years before she was fired a year ago. He said she had been a good employee.

“No conversation was ever heard on my end about her speaking about President Obama,” Evans told Jiang.

He said Carey had been away from the job for a period after falling down a staircase and suffering a head injury, and she learned she was pregnant during the time she was hospitalized. He said it was a few weeks after she returned to the office that she was fired.

“When she came back — she was here a few weeks later — we just decided that it was time for her to go,” Evans said, but would not elaborate on why she was fired, Jiang reported.

“We’re shocked to know this happened and we feel saddened for her family and all those involved,” Evans added.

Miller reported Carey was fired after a fight with her bosses over her using a handicapped parking space they felt she didn’t need.

Carey grew up in the Bedford-Stuyvesant section of Brooklyn, friends told CBS 2. Her friends in the neighborhood said they saw her there earlier this week.

“I don’t understand,” said friend Donald Knowles. “She was just here. When I did see her, she was just hug, all smiles.”

Her family gathered at a home in Bed-Stuy Thursday night. They did not talk to reporters, but the family’s lawyer did speak.

“It’s like anyone else — how would you feel?” said attorney Eric Sanders. “You see these things happen to people and you wonder how did this happen. It’s out of the ordinary. So of course they’re shocked.”

Police said there appeared to be no direct link to terrorism and there was no indication Carey was even armed.

Capitol Police Chief Kim Dine, whose officers have been working without pay as a result of the shutdown, called it an “isolated, singular matter.”

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