Doctor suspected in D.C. gym shooting had ongoing lawsuit against condo association

A doctor suspected of killing a building manager and wounding four other people at a Washington, D.C., condominium complex on Thursday had been pursuing a lawsuit over alleged mold and water damage in his home. Officials said Dr. Matt Lambert, 55, was later found dead in his apartment from an apparent self-inflicted gunshot wound.

The shooting began shortly after 8 a.m. at the VIDA fitness center on the ground floor of the Metropole, a seven-story luxury building in Logan Circle, about a mile from the White House. A witness exercising on a treadmill initially mistook the first shot for an exercise ball bursting. Another told NBC News he saw someone fall from a chair with a bleeding head. Patrons rushed outside after a fire alarm sounded, and some took shelter in a nearby bagel shop.

Federal and local law enforcement officials told NBC News that Lambert entered the gym seeking a particular person and spared others before leaving and firing more shots. He then returned to his apartment and barricaded himself inside. Metropolitan Police Department interim Chief Jeffery Carroll said the gunman shot four people at ground level from his balcony. Officials said he also fired through his apartment door into the hallway before killing himself.

Carroll identified the person killed as James Stuart, 46, a building manager from northwest Washington. Three surviving victims had injuries that were not life-threatening, while another was in critical condition. Carroll said investigators believed the violence was connected to Lambert’s maintenance dispute with the condominium association and building management. Lambert’s lawyer, Joel Braithwaite, described Stuart as a central factual witness in the civil case.

Lambert sued the Metropole Condo Association and property manager EJF Real Estate Services Inc. in March 2025, amending his complaint in July. He alleged that work on the building’s facade in 2024 caused water damage to his seventh-floor condominium. Property records show he bought the unit in 2016 for more than $1 million. His complaint said repeated investigations and two independent assessments identified moisture, mold and water intrusion, but the defendants failed to adequately address those conditions.

According to the lawsuit, Lambert eventually hired workers himself to handle mold contamination. He claimed more than $300,000 in damage and sought compensation for expenses including inspections, temporary accommodation, relocation and storage. The defendants denied his allegations. The case remained active, with remote mediation scheduled for March.

In a separate complaint filed in December 2025, the condominium association attributed any damage to other parties, including VIDA operator Urban Adventures Companies Inc. Citing an engineering consultant’s findings, it alleged that gym dryers and a failing exhaust system likely increased moisture levels. Representatives and attorneys for the association and EJF did not immediately answer requests for comment Thursday. A VIDA lawyer also did not immediately respond.

Lambert frequently posted about the dispute on X using the name OfMiceandMold. At 8:06 a.m. Thursday, he shared what he described as an engineering report about his condominium. Braithwaite said Lambert had been in Orlando that week for a speaking engagement and was due to begin a medical and artificial intelligence job Monday. The lawyer said Lambert appeared to be in a good place when they spoke Tuesday.

Police recovered a handgun, rifle and shotgun from Lambert’s apartment. Carroll said investigators believed he used all three during the shooting and that there had been some planning. How he obtained the weapons remained unclear. The chief said Lambert had no firearms registered in his name in Washington.