D.C. Doctor Accused of Killing Condo Manager as Account Exposes $300K Year-Long 'Of Mice and Mold' Feud

Police say Matt Lambert, a doctor, shot five people at VIDA Fitness, a Washington DC gym. Among them was James Stuart, 46, the manager of his condo building, who died. Police said Lambert was in conflict with the building's managers, and court records show he sued its condo association in March 2025.

An X account thought to be his, @OfMiceandMold, had chronicled the feud for over a year. His lawyer, Joel Braithwaite, said Lambert had put over $300,000 (£226,000) of his own money into the dispute, CNN reported. He died after an hour-long standoff; officers said he took his own life.

What Police Say Happened at VIDA Fitness

Lambert opened fire shortly before 8am at VIDA Fitness on 15th Street NW, in the Logan Circle neighbourhood. About 50 people were exercising there, a gym member told the Associated Press. Interim police chief Jeffery Carroll said Lambert shot Stuart inside the gym, then went up to his seventh-floor apartment in the same building. From his private patio, he fired at four others below. The department's first public alert appears below.

The whole attack lasted about five minutes, Carroll added. Lambert then barricaded himself inside and twice fired through his door at officers. After about an hour of negotiations by phone, police entered and found him dead. Investigators recovered three guns from the apartment: a handgun they believe Lambert used in the attack, a rifle, and a shotgun. Lambert had told the Washington Sun last year that Stuart came to the gym at about 8am.

Inside the Mould Lawsuit

His lawsuit claimed facade renovation work caused water intrusion and mould in his penthouse. The Metropole Condominium Association denied the claims. In a later filing, it alleged VIDA Fitness's dryers and a failing exhaust system may have caused excess moisture. By November 2024, his contractors had stripped walls and floors, finding black mould, the suit says. He paid $1.095 million (£824,000) for the penthouse in 2016, tax records cited by NBC Washington show, but said it was unusable from 2024.

Stuart testified about Lambert's reports, court records cited by City Cast DC show. Carroll cited an ongoing dispute over maintenance and the civil case Lambert filed, adding: 'So we believe that it's related to that.' The X account's posts, which began in October 2025, complained of mould, pests, and water damage, NBC News reported. Others showed notices about broken gym dryers, which the association cited in its defence. Its last post came at about the time of the shooting.

What Happens Next

Councilmember Brooke Pinto, who represents the area, called the killing 'a really targeted murder' on Fox 5 DC. Braithwaite also told NBC Washington that Stuart had a role in the dispute. A lawyer who represented Lambert in the condo lawsuit told CNN he had seemed calm and non-violent.

Carroll said one of the four wounded, two men and two women, was in critical condition and three had injuries that were not life-threatening. They included builders working across the street. David von Storch, who owns VIDA Fitness, said the shooting had left him devastated.