By Leah Douglas and Jonathan Ernst
WASHINGTON, Nov 12 (Reuters) - One person was killed and four others were shot and wounded when a gunman opened fire inside a gym before barricading himself inside an apartment building in Washington, DC, on Thursday morning, police said.
The suspect holed up inside a seventh-floor unit, where police negotiators were able to open a dialogue, Metropolitan Police Interim Chief JW Carroll told reporters. After about an hour, police heard a gunshot and forced their way
into the apartment, where they found the suspect with a self-inflicted gunshot wound.
The suspect's condition was not immediately clear, but NBC and Fox News reported he had died, citing unnamed law enforcement sources. Carroll said police believe he lived in the apartment and was a member of the gym where the attack began.
The shooting began just before 8 a.m. ET (1300 GMT), and officers arrived within 30 seconds, where they discovered an adult male shot. Police were clearing a nearby apartment building when gunshots rang out on the seventh floor where the suspect had barricaded himself, Carroll said.
Police did not identify either the suspect or the deceased victim. One of the four wounded people is in critical condition, Carroll said.
Investigators are working to determine a motive, Carroll said.
The shooting drew a massive police response, with large numbers of officers in tactical gear flooding the area in the Logan Circle neighborhood, about a mile (1.6 km) northeast of the White House.
One person who described himself as having witnessed the incident told Reuters that he heard gunshots and saw one man run to another who had apparently been struck by a bullet.
"Blood was pouring immediately, and he said, 'He's dead,'" the witness said. "We didn't know if the gunman was still on the premises, so we just ran frantically."
He said he heard more gunshots after running away from the gym.
(Reporting by Jonathan Ernst, Susan Heavey and Katharine Jackson in Washington, writing by Joseph Ax; editing by Scott Malone and Chizu Nomiyama)
