Who Was Matt Lambert? Doctor's Manifesto Reveals Bitter Mould Dispute Before Deadly Washington DC Gym Shooting

Dr Matt Lambert, an emergency-room physician preliminarily identified as the suspect in a Washington DC shooting that killed one person and injured four others, was linked to an online post declaring: 'My manifesto is an engineering report.' The material described alleged mould and water damage at his condominium.

The post appeared on the morning of 12 November, amid a property dispute in which Lambert alleged his penthouse had been unusable since 2024. Ward 2 councillor Brooke Pinto said preliminary information connected the initial attack to a condominium dispute, although investigators had not established a definitive motive.

Matt Lambert's Mould Dispute Reached the Courts

Lambert filed a lawsuit against the condominium association in 2025, alleging that mould, moisture and water problems had prevented him from using his penthouse since the previous year. He attributed the damage to work carried out on the building's exterior.

The litigation was still ongoing, with mediation scheduled for March 2027, rather than having ended in a final ruling against him. His account of the damage and its causes remained allegations, not judicial findings establishing responsibility on the part of the association or the contractor.

Online Post Called Report a 'Manifesto'

An X account called OfMiceandMold, on which Lambert appeared to share his condominium complaints, published the post referring to an engineering report that morning. The account had previously featured complaints about alleged leaks, mould and rodent problems, but its ownership had not been publicly authenticated by investigators.

The linked document mentioned 'suspected microbial growth', water damage and an estimate to restore an apartment wall, rather than confirming black mould. The available reporting did not establish its authorship or full technical conclusions, or indicate that it contained a threat or referred to planned violence.

Who Is Dr Matt Lambert?

Lambert was described as an emergency-room physician in coverage of the online material and lived in the condominium building where the police operation unfolded. VIDA Fitness occupied the building's ground floor, while his apartment was upstairs.

Two law enforcement officials identified the suspect as Lambert to journalists, although police had not publicly released his name when the initial identification appeared. Interim Metropolitan Police Department chief Jeffery Carroll said investigators believed the suspect lived in the building and was a member of the gym.

Councillor Described a Possible Condominium Link

Pinto said preliminary information suggested the gunman entered VIDA Fitness to target someone connected to a condominium dispute involving him. She distinguished the initial shooting from the subsequent gunfire outside, which did not appear to be as targeted.

Carroll described an apparent conflict involving the apartment building, while the lawsuit and online complaints provided further background to the dispute. The intended target's precise role remained unclear, and the preliminary accounts did not establish that the person was responsible for the alleged property damage.

Washington DC Shooting Ended in a Barricade

The shooting began around 8am, when the gunman killed a man inside the gym before fleeing and shooting four other people, officials said. One injured victim was in critical condition, while the other three had injuries that were not considered life-threatening.

Officers said the suspect fired through an apartment door before negotiators contacted him by telephone, then heard a gunshot during the conversation. Police subsequently found him with a self-inflicted gunshot wound and he was pronounced dead, bringing the overall death toll to two, including the suspect.

VIDA Fitness announced that its Logan Circle branch would remain closed until further notice and asked people to avoid the surrounding area during the emergency response. Nearby schools were placed on alert and roads restricted as federal agencies assisted local police.