Miriam Carey, 34, was killed after she rammed a gate at the White House with her car, then fled through Washington streets at speeds of as much as 80 mph before she crashed her car near Capitol Hill, where she was shot. A 1-year-old child was found, unharmed, in the back seat of Carey's car after the shooting.
Capitol Police and the Secret Service fired shots at her as she sped away from the White House. At the Capitol, police said, she attempted to make a U-turn and head toward officers.
No weapons or explosives were found in the car, The New York Times reported Friday.
The Washington police department is leading the investigation into what threat police believed she posed to them and others.
That department, like many others, has a policy forbidding officers from firing at moving vehicles.
"A moving vehicle is not considered deadly force," the Washington policy reads.
Chuck Wexler, executive director of the Police Executive Research Forum that recommends the policy, said it might not apply in this case.
The White House and the U.S. Capitol are "high risk targets," he said.
"The people who protect the White House and the people who protect the Capitol are not thinking about your everyday criminal. They are thinking about a terrorist."
Carey family attorney Eric Sanders said the family wants to know "if protocols were followed," CNN reported.
Her sister, Amy Carey, said Miriam had become depressed and psychotic after giving birth and had received "treatment and medication and counseling." However, "she didn't appear to be unstable."