Police Cpl. Shawn Vinson, the police department's spokesman, said law enforcement agencies are searching for at least one suspect who is possibly still armed.
Though the governor initially said she died after being shot, police later said they could not confirm exactly how she died. The officer was transported to MedStar Franklin Square Medical Center, about seven miles away.
A female, four-year veteran of the Baltimore County Police Department officer was killed in the line of duty Monday afternoon, though initial reports are unclear as to how her cause of death.More news: Top alpinist Nobukazu Kuriki dies in eighth attempt to conquer Everest
SkyTeam 11 Capt. Roy Taylor reported the suspect or suspects left the scene in a Jeep Wrangler, then bailed out of the vehicle in the area of Pine Hill and Belair roads. His fellow officer died in the incident.
Police are searching for "at least one armed suspect" in the area of Belair Road and Klausmeier Road, and residents should shelter in place, officials said. The auto left skid marks behind, he said, leaving the officer down and bleeding.
Larry Hogan confirmed the death, saying "we're deeply saddened" that the "brave officer" was shot in the line of duty. She was directed out of the area by police, but was concerned about her children who were home at the time of the shooting.More news: Ex-Malaysian prime minister Najib Razak questioned over 1MDB corruption scandal
He said the officer was responding to a report of a suspicious vehicle in the neighborhood.
Vinson added that she immediately received treatment after neighbors called authorities, but was pronounced dead on arrival at a hospital. "And so we're telling everybody to be on your toes, don't be complacent, to work with each other".
The police chief said that Americans are "seeing something in this country we've never seen before". "Our prayers go out to this courageous officer's family, @BACOPoliceFire, and the Baltimore County community". "We are proud of the bravery and courage and sacrifice of all the men and women who serve on our police force". Vinson said the patio door of a home at the scene showed some damage, suggesting a burglary was in progress. Baltimore County Public Schools said in a statement that the alert status placed on three elementary schools does not involve a lockdown. But by Monday evening, parents were allowed to come to the schools to pick up their youngsters.More news: Where did Charlotte and George go?
Vincent said the fatal confrontation happened at the end of a cul-de-sac on Linwen Way off Belair Road in a heavily residential area of Perry Hall.