The gunman in the early morning Washington, DC, gym shooting has been identified as a well-heeled doctor who was battling his homeowners’ association over black mold in his $1.1 million apartment and railed about it on X.

Dr. Matt Lambert, an emergency room doctor, had sued Metropole Condominium Association in March 2025, alleging repairs to the building, which involved it being surrounded by scaffolding and drapes, led to mold festering in his home.

“Two years of living in luxury (and the start of 6 months with no shower, dryer, HVAC, and cooking),” an X account linked to Lambert posted Wednesday, along with pictures showing renovations in the unit.

Lambert, who lived on the seventh floor of  1515 15th St. NW, opened fire Thursday morning inside the ground-floor gym, killing at least one person. He then ran back up to his apartment and barricaded himself for nearly an hour before he killed himself.

DC police said they were investigating a conflict with the homeowner’s association as the reason behind the shooting, which left one dead and four others injured.

Lambert filed his suit in March 2025, alleging that his home experienced “no significant water intrusion, mold, moldy smells, moisture accumulation, or related damage,” prior to the remediation efforts overseen by the association.

But, after the building was enveloped, his unit “experienced suspected water intrusion, mold, significant moisture accumulation, and/or related damage,” the suit said.

Ward 2 Council Member Brooke Pinto, who represents and lives in the area, said preliminary information suggests the shooter was targeting someone in Vida Fitness and “that he had been in active litigation with over a condo issue.”

“It’s just so sad and so senseless to kill someone over a dispute that should be worked out reasonably,” she told NBC News.