(CNN) -- A day after Miriam Carey ran a barricade and led police on a high-velocity chase through the middle of the nation's capital, authorities were searching for clues to explain the bizarre chain of events that led to her death.
Although Carey was shot while driving with her baby, the child was uninjured.
Many questions surrounding those facts remain.
Here's what we know about Carey, a 34-year-old who reportedly had worked as a dental hygienist in Connecticut.
Boyfriend: She thought the president was monitoring her
A law enforcement source involved in the investigation said Thursday that Carey's boyfriend had told police last winter that she appeared to be delusional. The boyfriend said she claimed President Barack Obama had placed Stamford, Connecticut, where she lived, under lockdown and that her house was under electronic surveillance, the source said.
He told police that she was suffering from postpartum depression, was having trouble sleeping and was on medication. Carey underwent a mental health evaluation, the source said.
Authorities have not officially linked the incident to mental illness or any other factor.
A few months after her daughter was born, Miriam Carey was diagnosed with postpartum depression with psychosis, her sister told CNN's AC360.
Postpartum psychosis can cause delusions and paranoia, according to medical experts.
"There wasn't a pattern. It was something that occurred suddenly," Amy Carey-Jones said. "She seemed overwhelmed. There was a lot of stress.
"There was not moments of her walking around with delusions. That was not what was going on."
But her sister was making progress with the help of counseling and medications.
Carey-Jones said her sister recently told her that the doctors told her she didn't need the medication anymore. "They tapered her off the medications, and she said she felt fine," Carey-Jones said.
She declined to discuss what medication Miriam Carey had taken.
Carey lived in an apartment that authorities searched Friday.
During the search, authorities found discharge papers from a 2012 mental health evaluation that listed prescriptions for medications to treat depression, schizophrenia and bipolar disorder -- a law enforcement source briefed on the investigation said Friday.
Earlier, sources said investigators found medications, but that proved later not to be accurate.
Authorities found a laptop computer, a flash drive and three non-working cell phones, the source said.
The source told CNN that Carey left a letter addressed to the boyfriend at her apartment and that it appeared to contain white powder. The letter was being tested for hazardous substances.
The baby girl
After surviving a high-speed police chase with Carey at the wheel, authorities placed the girl with a foster family, a spokesperson for Washington's Child and Family Services Agency told CNN. During the chase, no shots were fired from the Infinity, CNN's Deborah Feyerick reported. All shots were from law enforcement directed at the passenger side of the car.
New York relatives
In Brooklyn in New York City, where Carey's mother and one of her four sisters live, a neighbor reported seeing the suspect Tuesday picking up her daughter. When federal agents arrived to conduct questioning, no one at the apartment answered the door. Carey's Facebook page includes a map pinpointing Stamford and New York.
CNN's Chelsea J. Carter, Carol Cratty, Deborah Feyerick, and Joe Johns contributed to this report.