(CNN) -- A young mother is dead and her year-old child is in protective custody.
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 she was shot while driving with her baby, the child survived unhurt. But 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 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.
Carey lived in an apartment that authorities searched Friday.
During the search, authorities found a medication to treat schizophrenia and bipolar disorder, and another medication that is an antidepressant, according to the law enforcement source, who was briefed on the investigation. They also found a laptop computer, a flash drive and three non-working cell phones.
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 Carol Cratty, Deborah Feyerick, and Joe Johns contributed to this report.