DC shooter identified as 55-year-old doctor Matt Lambert who sued HOA over black mold in apartment

Per the New York Post, Lambert, 55, lived on the seventh floor of 1515 15th St NW in a $1.1 million penthouse. The apartment building is located above the Vida Fitness gym, where a person was found dead by police on Thursday morning after being shot. After carrying out the shooting, Lambert, who police said was also a member of the gym, barricaded himself inside the penthouse.

An X account linked to Lambert tweeted at 8 am, around the time the shooting began, “my manifesto is an engineering report.” Lambert had sued his homeowners association in March of 2025, claiming that black mold had spread in his apartment after repairs were done to the building’s facade and seeking funds to “rehabilitate” the wall of his apartment.

The post attached a report citing “suspected microbial growth” and water intrusion. The suit alleged that his home had experienced “no significant water intrusion, mold, moldy smells, moisture accumulation, or related damage” before the homeowners association oversaw remediation efforts. After the renovation, however, he said his unit “experienced suspected water intrusion, mold, significant moisture accumulation, and/or related damage.”

Interim Chief of Police for the Metropolitan Police Department Jeffery Carroll said at a press conference Thursday, “We do know there was a conflict between him and the homeowners association of that building, but at this point, we’re continuing to look into that.”

Ward 2 Council Member Brooke Pinto said that preliminary information had suggested Lambert was targeting a person in Vida Fitness and “that he had been in active litigation with over a condo issue.”

The X account linked to Lambert is filled with numerous posts about “leaks, mold and rodent infestation.” Lambert had reportedly been fighting with the Metropole Condominium Association over mold problems since August 2024.

“It’s a good night to have an uninhabitable penthouse,” he posted in July. An October post read, “Discontinuous Tyvek should be the name of a punk band- not something listed in the conclusions of a building envelope report.”

A post on Wednesday read, “Two years of living in luxury (and the start of 6 months with no shower, dryer, HVAC, and cooking),” and included photos showing the state of the inside of his unit.