The gunman who killed one person and injured four others in Washington, DC before barricading himself in a condo building on Thursday morning was an emergency room doctor who had been locked in a legal dispute with the buildingâs management over a mold problem in his unit.
Police identified Matt Lambert as the shooter who died of a self-inflicted gunshot wound after shooting several people in the gym and parking garage of the Metropole, a luxury condo building near Logan Circle. Lambert sued the Metropole Condominium Association in March 2025, alleging that the associationâs maintenance work had caused water and mold damage in his penthouse condo unit.
An account on the social media network X, which had posted court documents from Lambertâs dispute, sent a message at 8:06 a.m. on Thursday â around the time of the shooting â declaring that "my manifesto is an engineering report," and including a screenshot of a report seemingly describing damage in Lambertâs unit.
Two witnesses told CNN that Lambert placed phone calls shortly after the building was evacuated to explain his actions. One of the witnesses, Sean McClafferty, who lives in the Metropole, says he was standing with the buildingâs concierge a block away when the concierge received a phone call from Lambert. "Essentially, he told our concierge, âThis is what I need to do to get attention,â" McClafferty said.
A second witness, who asked not to be named, said he heard Lambert say over the phone that this was how he decided to resolve his dispute with the buildingâs board. Lambert bought his 1,200-square-foot unit for just over $1 million in 2016, property records show.
According to Lambertâs lawsuit, his unit experienced damage from "suspected water intrusion, mold, (and) significant moisture accumulation" caused by work to renovate the buildingâs façade starting in 2023. By September 2024, the unit was showing signs of water damage, but the condo association denied that mold was present and was "ignoring Plaintiffâs very real mold complaints," the lawsuit stated.
In November 2024, Lambert hired a company to remove the unitâs mold-contaminated walls and flooring. He said in the lawsuit that he avoided using his shower or HVAC system for six months, but the unit continued to experience excessive moisture. Lambert also hired a firm to conduct further testing in May 2026, which identified "microbial contamination and/or mold growth" in the unit, according to court documents.
Lambert had spent more than $290,000 investigating and responding to the damage as of May, according to the complaint. In court documents, the condo association and its property management company denied some of Lambertâs claims and argued that the association "did not cause the Plaintiffâs alleged injuries and damages." The case was scheduled to go to a mediation session in March 2027, court records show.
An attorney who had represented Lambert in his lawsuit against the condo association described his client in an interview with CNN as calm, conscientious, and nonviolent, and expressed shock at the idea that he was responsible for the shooting. That attorney added he thought the lawsuit had been going well.
Lambert was born and grew up in Parkersburg, West Virginia, according to the Amazon description of a memoir he published. Lambert wrote on a personal website that he had more than two decades of clinical experience and has worked at various health care technology companies.
He received his medical degree from Marshall University in West Virginia, and completed a residency at West Virginia University, according to the website.
