D.C. man buys $1.1m penthouse and says it tested his ‘resilience’ for years, then he walks into the gym one day and allegedly shoots the building manager

Washington, D.C., was on high alert on Thursday morning when an active shooter opened fire at a local gym, killing one before fleeing the scene and wounding four more from the balcony of his seventh-floor penthouse apartment. Police found the shooter dead hours later from an apparent self-inflicted gunshot wound, following a phone conversation with negotiators.

The suspect was identified as 55-year-old Dr. Matt Lambert, a physician and healthcare consultant, the Associated Press reports. Police identified the victim as James Stuart, 46, the building manager at the D.C. condominium where Lambert lived. Lambert purchased the $1.1 million penthouse in the Logan Circle neighborhood in 2016, about a mile from the White House, where Cole Allen allegedly attempted to assassinate President Trump at the Correspondents’ Dinner in April.

“The whole incident took place in less than five minutes,” said Metropolitan Police Department Interim Chief of Police Jeffery Carroll. “I can only imagine being in that area and hearing the gunshots or being inside the gym.”

This started because of a dispute over mold and water damages

According to Carroll, Lambert had been embroiled in an ongoing legal dispute with the building management. A lawsuit filed by Lambert alleges that his apartment had mold, moisture, and water problems after a contractor worked on the building’s exterior. He maintained an X account, OfMiceandMold, which he described as a manifesto.

A report from The Washington Sun chronicles the dispute between Lambert, Stuart, and building administrators. In December, Lambert claimed he spent almost $200,000 on legal and engineering fees, borrowing against his retirement savings. The damage stripped his apartment down, forcing him to live with only a couch and a desk.

“I pride myself in my resilience, and I’ve been kind of surprised at how much it has been affected,” Lambert said in a December interview. “If I come out of this and I don’t get a satisfactory outcome, I won’t have a bunch of money, but I can live with that better than rolling over… They don’t have any permission to treat me this way.”

At 8:00 a.m. on Thursday morning, Lambert allegedly walked into VIDA Fitness, a gym located on the ground floor of his condominium, and shot Stuart in the neck. According to eyewitnesses, about 50 people were in the gym that morning. One witness, Anthony Mirones, said an onlooker tried to help Stuart when the fire alarm went off, and people rushed outside. “The people in cardio had to step over the body,” Mirones told reporters at the scene.

Lambert returned to his apartment upstairs and opened fire from his balcony. Following a standoff with D.C. police, he cut a natural gas line and started a fire, which was contained by the building’s sprinkler systems.

Lambert’s lawyer, Joel Braithwaite, told reporters that he was “deeply shaken and saddened”, adding that the apartment looked like a “war zone.” Last year, a similar incident occurred nearby when Rahmanullah Lakanwal allegedly shot two members of the West Virginia National Guard.