Law enforcement sources identified the gunman in Thursday’s fatal gym shooting in Washington, D.C., as Dr. Matt Lambert, who reportedly had an unresolved dispute with his homeowners association.
Two law enforcement officials and a person familiar with the case confirmed Lambert’s identity to The Associated Press, speaking on the condition of anonymity.
Authorities said the shooter opened fire at about 8 a.m. inside Vida Fitness in the Logan Circle neighborhood. One person died, four others were injured and the gunman was killed.
Law enforcement officers respond to an active shooter incident near Washington, D.C.’s Logan Circle on Nov. 12, 2026. (Annalise Peatel)
According to an Associated Press report, Lambert had been involved in a long-running dispute with the management of his apartment building. He filed a lawsuit against the company last year.
The AP reported that, less than 10 minutes before the first reports of gunfire, an X account called “OfMiceandMold” appeared to post, “My manifesto is an engineering report,” along with screenshots from the document. The account was reportedly linked to Lambert.
A secured area following a shooting in Washington, D.C., on Nov. 12, 2026. (Reuters/Aaron Schwartz)
Images posted to the account appear to document Lambert’s dispute with the Metropole Condominium Association, including complaints about mold and water intrusion in the building.
Law enforcement personnel work at the scene of a shooting in Washington, D.C., on Nov. 12, 2026. (USA TODAY Network via Reuters Connect)
The account contains a large collection of posts, photographs and videos alleging problems inside the apartment. In an early October post, the account accused the HOA of using what Lambert described as “months of ‘Luigi’ tactics” and referred to the submission of “an independent engineering report.”
The investigation into the shooting remains ongoing.