WASHINGTON (Diya TV) — A gunman killed one person and wounded four others Thursday morning at a fitness center in Washington’s Logan Circle neighborhood, then barricaded himself in a nearby apartment and died from a self-inflicted gunshot wound during a standoff with police.

The shooting began shortly before 8 a.m. at VIDA Fitness, on the 1500 block of 15th Street NW, about a mile north of the White House. Metropolitan Police interim Chief Jeffery Carroll said officers arrived within 30 seconds of the first emergency call. One man died at the gym. Of the four injured people, one remained in critical condition and three had injuries that were not life-threatening. Police had not released the victims’ names.

Authorities have preliminarily identified the gunman as Matt Lambert, a physician, according to people familiar with the investigation. Police have not publicly confirmed his identity or established a motive.

Carroll said the gunman fired at several locations around the gym before entering a nearby condominium building. Officers searching the building came under fire from a seventh-floor apartment. The gunman fired through the apartment door at police at least twice, Carroll said.

Negotiators spoke with him by phone for about an hour. After officers heard a gunshot and lost contact, they entered the apartment and found him with a self-inflicted wound. Authorities later confirmed his death.

Witnesses described a chaotic evacuation. James Spellman, who was at the gym, estimated that about 50 people were inside when the shooting began. He saw a man fall and said another gym member rushed to help. Mirones, who was in the cardio area, initially thought a loud bang came from something falling. Then a fire alarm sounded, and people ran from the building. Some had to pass the wounded man as they evacuated. Outside, witnesses heard more gunshots and scattered for safety.

The investigation has focused partly on a dispute between Lambert and the condominium association. Carroll said the gunman complained about the homeowners association during negotiations. Court records show Lambert filed a lawsuit last year alleging that building work led to water intrusion, mold and moisture damage in his apartment. Those claims describe the dispute; they do not establish why he opened fire.

D.C. Councilmember Brooke Pinto said preliminary information suggested the gunman targeted someone at the gym with whom he had an active condo-related legal dispute. Police have not confirmed that account or publicly identified the person who died.

Police also responded to a fire inside the condominium building. Officials said crews contained it, but had not confirmed who started it. The shooting prompted a shelter-in-place order, street closures and lockdowns at nearby schools. SWAT officers and federal agents assisted local police as authorities secured the block.

The block includes the fitness center, residences, a church and a grocery store. Mayor Muriel Bowser said the White House had been briefed and called the shooting a “senseless act of gun violence.” VIDA Fitness closed its Logan Circle location until further notice.

Investigators continue to establish the precise sequence of the shootings, identify the victims and determine what led to the attack.