The gunman responsible for Thursday morning’s deadly shooting at a luxury condominium building in Washington, DC, has been identified as Dr. Matt Lambert, an emergency room physician who had been involved in a bitter legal dispute with his homeowners’ association over alleged mold damage inside his $1.1 million apartment. The shooting left one person dead and four others injured before Lambert barricaded himself inside his residence and took his own life.

The violence erupted at the Metropole condominium complex in the Logan Circle neighborhood, where Lambert lived in a seventh-floor apartment above a Vida Fitness gym. Authorities said the physician opened fire inside the fitness center before retreating upstairs, triggering a massive police response and an approximately hour-long standoff.

Investigators are examining whether Lambert’s longstanding conflict with the condominium association motivated the attack. The dispute centered on extensive building renovations that Lambert claimed had caused water intrusion, moisture accumulation, and mold contamination inside his home.

Lambert had filed a lawsuit against the Metropole Condominium Association in March 2025, alleging that construction and remediation work had left the building covered in scaffolding and protective sheeting, creating conditions that damaged his apartment.

According to the lawsuit, Lambert’s residence had experienced “no significant water intrusion, mold, moldy smells, moisture accumulation, or related damage,” before the association undertook the work.

After the exterior construction began, however, the apartment “experienced suspected water intrusion, mold, significant moisture accumulation, and/or related damage,” the complaint alleged.

The physician had also publicly complained about the situation on social media, posting photographs of the apartment’s deteriorating condition and describing the disruption caused by the renovations.

On Wednesday, just one day before the shooting, an X account associated with Lambert posted photographs of the ongoing work and described the difficulties he claimed to have endured.

“Two years of living in luxury (and the start of 6 months with no shower, dryer, HVAC, and cooking),” the account stated.

Police said Lambert fled to his apartment following the shooting and barricaded himself inside as officers surrounded the building. The confrontation ended when he fatally shot himself.

The attack prompted a large emergency response in the upscale neighborhood, with police officers, tactical personnel, and medical crews converging on the building as authorities worked to secure the scene and assist the wounded.

Lambert described himself professionally as “a board-certified emergency physician with over two decades of clinical experience” and also worked as an executive in the medical technology industry.

His personal website highlighted his experience at the intersection of medicine, technology, and healthcare policy.

“He has a deep understanding of healthcare regulations and their impact on technology adoption,” the website stated.

Lambert also described dividing his time between the “mountains of West Virginia and the Logan Circle neighborhood of Washington, DC.”

DC Council Member Brooke Pinto, whose district includes Logan Circle, said preliminary information suggested the gunman had deliberately targeted an individual at the fitness center who was connected to his ongoing condominium dispute.

Pinto said investigators believed Lambert had been involved in litigation with the intended target “that he had been in active litigation with over a condo issue.”

“It’s just so sad and so senseless to kill someone over a dispute that should be worked out reasonably,” Pinto told NBC News.

Additional accounts from the scene indicated that the violence began shortly before 8 a.m., when gym members were exercising inside the facility. Witnesses described hearing gunfire, seeing a wounded man collapse, and rushing toward the exits as alarms sounded.

Police said the gunman subsequently shot four additional people, including one victim who remained in critical condition. The other three survivors sustained injuries that were not considered life-threatening.

During the standoff, officers established telephone contact with Lambert in an attempt to negotiate his surrender. Authorities said he fired through doors at least twice before a final gunshot was heard. Tactical officers entered the apartment and discovered him suffering from a self-inflicted gunshot wound.

The emergency prompted nearby schools to impose lockdowns, residents to shelter indoors, and police to close several surrounding streets. Federal law enforcement personnel also assisted local authorities.

Investigators have not established whether all five victims were deliberately targeted or whether some were struck as the gunman moved through the building. The identity of the person killed had not been publicly confirmed in the initial reports.