An angry tenant fatally shot his building manager and injured four others in an affluent Washington neighborhood on Thursday before taking his life, police reported, as a huge law enforcement operation brought part of the city to a standstill.

The shooting took place roughly a mile north of the White House and triggered a large-scale police mobilization across the capital, with dozens of law enforcement vehicles speeding to the site and police helicopters circling above.

Dramatic dispatch recordings captured the first emergency call reporting a shooting inside the gym shortly before 8 am (0100 GMT). Within moments, an out-of-breath officer was heard informing the dispatcher that “we have an active shooter” and calling for the SWAT team.

Jeffery Carroll, Washington’s interim police chief, told reporters that the gunman, identified as 55-year-old Matt Lambert, had been locked in a long-running maintenance dispute with the condominium association for the building where he owned an apartment.

Lambert, an emergency medicine physician, shot and killed the building manager, 46-year-old James Stuart, inside a crowded gym attached to the complex in the Logan Circle neighborhood. According to Carroll, Lambert then barricaded himself inside his seventh-floor unit.

After that, he fired from his balcony at people below, wounding four of them. One of the injured was listed in critical condition, while the others suffered injuries that were not life-threatening.

Citing a company executive, The Washington Post reported that construction workers from a nearby jobsite were among those hurt.

Carroll said Lambert fired at least two shots at police through his apartment door and set the unit ablaze before turning the gun on himself. He was declared dead at the scene.

Photos and video quickly spread on social media showing police in tactical gear with rifles drawn surrounding the building, along with flames coming from an exterior wall.

Carroll said Lambert had filed legal action against the homeowners association of the condominium complex where he lived, claiming the building was not being properly maintained.

An X account reportedly tied to Lambert under the handle @OfMiceandMold is filled with complaints about mold and water damage. The last post, described as a “manifesto,” is an engineering report laying out problems with his apartment.

Washington Mayor Muriel Bowser condemned what she called a “senseless act of gun violence.”

The shooting happened during the busy morning rush hour, backing up traffic as police shut down streets around the area and evacuated residents.

The Washington Sun quoted a VIDA Fitness gym member as saying he was on a treadmill at the facility when the gunfire broke out.

Michael Carney said he heard a “pop” and then saw a person on the gym floor who had been shot in the head.

“People were basically just ducking behind planters and whatever else they could find,” Carney told The Sun.

On Thursday night, church groups gathered Logan Circle residents for vigils and prayers close to where the shooting happened.

According to the Washington Post, the local government has declared the building unsafe to live in due to fire damage, and residents have been told to stay away.

Logan Circle is among the priciest neighborhoods in Washington and is famous for its stylish restaurants and nightlife. It is also located just a short distance from a dense cluster of foreign embassies.