Around 6:40 a.m. on Saturday, the authorities responded to a residential neighborhood in Woodlawn, Md., an unincorporated area about 12 miles west of Baltimore.
When the police arrived, they found an armed man outside of a townhouse, and the “threat was neutralized,” said Joy Stewart, a spokeswoman for the Baltimore County Police Department.
The gunman, who was not immediately identified, was later pronounced dead.
Three other victims, two men and one woman, also died. It was not immediately clear how they died. A fifth victim had injuries that were not life-threatening, the authorities said.