(RNN) - Miriam Carey, the woman who led police on a chase through Washington, DC, that ended in her death, thought President Barack Obama was communicating with her, according to a federal official.
The Associated Press reported Friday that law enforcement believed she was delusional after interviewing members of her family. Investigators also found medication used to treat bipolar disorder and schizophrenia symptoms inside Carey's apartment Friday.
A law enforcement source told CNN an antidepressant was also found in the Stamford, CT, residence. WFSB reported police evacuated residents around the apartment Thursday and a robot was used to ensure it was safe; nothing hazardous was found inside.
Carey, 34, was shot and killed by police after she tried to breech security barriers at both the White House and Capitol, leading to a high-speed chase between the two buildings.
Carey's mother, Idella Carey, told ABC News on Thursday that her daughter suffered from post-partum depression after giving birth in August. Miriam Carey's daughter, Erica, was in the car during the chase.
The 1-year-old was not seriously injured and has been taken into protective custody, according to the Associated Press.
"We'll never know what Miriam was thinking in those last hours before she died," her sister Amy Carey told CNN. "Our real concern is why and were things done properly. Was there some other way she could have been helped so that it didn't end tragically?"
Amy Carey said she talked regularly with her sister. Her last conversation on Monday was "normal, regular, business as usual," she said.
Amy Carey said her sister underwent counseling for a diagnosis of postpartem depression with psychosis.
"The dianogsis came a little after the birth of her daughter. I did recently ask her about the medication. She told me the doctors told her she didn't need the medication anymore because the plan was for her to come off the medication in a year," Amy Carey said.
Amy Carey called her sister a "great mom. She was very nurturing to her daughter."
"It's a shame that my mother, my sisters and I had to find out from reporters that called us and asked us to watch the news," said Valeria Carey on Friday night. "Shame on Metro D.C. area personnel for not informing us of what happened to my sister. No one deserves this."
Dramatic video captured by a photographer near the Capitol Thursday shows a black Infiniti, surrounded by officers holding guns, backing into a police cruiser, then speeding away.
Capitol Police Chief Kim Dine called the incident an "isolated event" and said there are no apparent ties to terrorism.
Carey was unarmed and police said the only shots fired were by officers.
Two officers, one from the Secret Service and a 23-year veteran of the Capitol Police, were injured during the chase but not seriously.
The incident prompted a lockdown at the Capitol, as well as at Senate and House office buildings.
The incident rattled a city which a little more than two weeks ago grieved the deaths of 12 people gunned down at the Washington Navy Yard.
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