Police in Washington could have avoided shooting dead a woman pursued by officers in a car chase that led to the lockdown of the Capitol this week, the driver's sister, former New York police sergeant Valarie Carey, said late on Friday.
The family of Miriam Carey, whose one-year-old daughter Erica was in the car with her during the encounter with police on Thursday, has said she suffered from post-natal depression.
Carey, 34, a resident of Stamford, Connecticut, tried to drive her black Infiniti coupe through a barrier near the White House, then sped toward Capitol Hill, leading police on a high-speed chase that ended when her car got stuck on a median and police shot her.
"My sister could have been any person traveling in our capital," Valarie Carey told reporters outside her Brooklyn home.
"Deadly physical force was not the ultimate recourse and it didn't have to be."
The chase and shooting came at a time of high political tension in the U.S. capital with Congress debating how to resolve the shutdown of the federal government. The Capitol was locked down after the shots were fired.
In another incident that caused alarm in Washington, a man appeared to have set himself on fire at the National Mall on Friday. He was listed in critical condition at a hospital.
Law enforcement sources said Carey did not shoot a gun and there was no indication she had one.
"I'm more than certain that there was no need for a gun to be used (by police) when there was no gunfire coming from the vehicle," Valarie Carey said.
"I don't know how their protocols are in DC, but I do know how they are in New York City."
Representatives from the Capitol Police and the District of Columbia's Metropolitan Police Department could not be reached for comment.
At the news conference in Brooklyn, Carey's other sister, Amy Carey-Jones, described to reporters the struggles her sibling had with post-partum depression.
"I can tell you that she was a law-abiding citizen, carefree and loving. She had a baby and she did suffer from post-partum depression with psychosis," Carey-Jones said, adding that her sister had been receiving medication and therapy.
The visibly emotional sisters held hands during the news conference. They had traveled to Washington earlier in the day to identify their sister to authorities with the use of photos, Carey-Jones said.
Investigators are focusing on whether Carey had mental problems that triggered her actions, said a US official, speaking on condition of anonymity.
Investigators have been interviewing Carey's family about her mental condition, which had been deteriorating over the past 10 months, the official said.
The woman had made delusional "expressions about the president in the past" and "believed there was some communications to her", and concerns about her mental health were reported in the last year to Stamford police, the official said.
Carey's mother, Idella Carey, told ABC News on Thursday night that her daughter began suffering from postpartum depression after giving birth to her daughter, Erica, in August 2012.
"A few months later, she got sick," she said. "She was depressed. ... She was hospitalised."
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 Erica to a doctor's appointment in Connecticut.
Connecticut records show Carey had been a licensed dental hygienist since 2009. Records show the license expired on Thursday.
Dr Brian Evans, a periodontist in Hamden, Connecticut, said Carey worked as a hygienist in his office for about two years before she was fired a year ago. He would not go into detail about the reasons surrounding her departure.
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 hospitalised. He said it was a few weeks after she returned to the office that she was fired.
Police said there appeared to be no direct link to terrorism, and there was no indication the woman 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".
Still, tourists, congressional staff and even some senators watched anxiously as a stream of law enforcement vehicles chased a black Infiniti with Connecticut license plates down Constitution Avenue outside the Capitol and as officers with high-powered firearms canvassed the area. The House of Representatives and Senate both abruptly suspended business, a lawmaker's speech cut off in mid-sentence, as the Capitol police broadcast a message over its emergency radio system telling people to stay in place and move away from the windows.
The woman's car at one point had been surrounded by police cars and she managed to escape, 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. Metropolitan Police Chief Cathy Lanier said police shot and killed her a block northeast of the historic building.
In Connecticut, the FBI served a search warrant in connection with the investigation and police cordoned off a condominium building and the surrounding neighbourhood in the shoreline city.
Jackson said Carey was upset earlier this summer when the tires were stolen off her car, but she said her neighbour seemed content. She said she never heard her say anything political.
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 US$1,759 (NZ$2112.15) in addition to collection costs, and indicates that she took out a mortgage on her condo in the amount of US$237,616.
The chain of events in Washington began when the woman sped onto a driveway leading to the White House, over a set of barricades. When the driver couldn't get through a second barrier, she spun the car in the opposite direction, flipping a Secret Service officer over the hood of the car as she sped away, said BJ Campbell, a tourist from Portland, Oregon.
Then the chase began.
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.
Congressman Michael McCaul, who said he was briefed by the Homeland Security Department, said he did not think the woman was armed. "There was no return fire," he said.