Miriam Carey Motive: Capitol Hill Shooting Suspect Believed Government Had House Under Electronic Surveillance, Boyfriend Claims

In the wake of the high-speed chase and shootout on Capitol Hill Thursday that resulted in suspect Miriam Carey being killed by police, authorities are piecing together the motive of the 34-year-old Connecticut woman.

Carey, a dental hygienist who reportedly suffered from a mental illness – specifically, postpartum depression -- acted “delusional” back in December, claiming the government had her home under electronic surveillance, according to her boyfriend and the father of their child.

News broke of the high-speed car chase on Thursday afternoon along Pennsylvania Avenue between the White House and Capitol Hill. Reports emerged around 2 p.m. that police were chasing a black Infiniti that had earlier struck the barrier of the White House gates. The vehicle then reportedly ran over an officer after attempting to breach the southeast gate.

The car, driven by a female later identified as Carey, sped down Pennsylvania Avenue en route to the Capitol, where Congress has been gridlocked in the midst of a government shutdown over President Barack Obama’s Affordable Healthcare Act and the federal budget.

Police surrounded the vehicle at Garfield Circle at the base of Capitol Hill near the Botanic Garden, but the female driver slammed her car into reverse and crashed into a police cruiser before getting away. That’s when police began shooting, witnesses said.

The chase continued when the vehicle circled the Peace Monument before driving up Constitution Avenue and crashed into another barrier at the Capitol. Police open fired on the black Infiniti with a Connecticut license plate, killing the unarmed suspect.

Authorities later found that the suspect was 34-year-old Miriam Carey, a Stamford, Conn.-based dental hygienist originally hailing from Brooklyn, N.Y. Carey’s 1-year-old child, a daughter named Erica, was discovered in the backseat of the car, present all along during the high-speed chase. The child was not injured, but Carey was fatally shot several times. Two officers suffered from injuries in the chase.

“I’m pretty confident this was not an accident,” Metropolitan Police Chief Cathy Lanier said, but police do not believe it was terrorism.

On Thursday night, Carey’s mother, Idella Carey, told ABC News that her daughter suffered from mental illness.

“She had postpartum depression after having the baby,” Idella Carey told ABC. “A few months later, she got sick. She was depressed. She was hospitalized.” Carey said her daughter had “no history of violence” and no idea why she was in Washington, D.C., as she was supposed to be taking her daughter to a doctor’s appointment in Connecticut on Thursday.

CNN reported that Carey’s apartment, a condominium complex in Stamford called Woodside Green, was being searched by police and bomb-squad units into the evening. Authorities did not find any explosives in Carey’s apartment, but a source told CNN that Carey left a letter to her boyfriend that contained “white powder.” The anonymous source told CNN that it was being tested.

The boyfriend, who was not identified by CNN, reportedly called the police for help in December, claiming he feared for their then-4-month-old child’s safety because Carey was acting delusional and thought “the president had placed Stamford under lockdown and that her house was under electronic surveillance.”

Her boyfriend was reportedly being questioned by federal authorities following Thursday's incident in D.C.

Carey’s boss of eight years, Dr. Steven Oken, said his employee was a “nonpolitical person” who was “always happy.”

"I would never in a million years believe that she would do something like this," he told ABC News. "It's the furthest thing from anything I would think she would do, especially with her child in the car. I am floored that it would be her."