Matt Lambert, MD, a 55-year-old emergency medicine physician and longtime health technology executive, has been identified by police as the gunman who killed one person and wounded four others Nov. 12 in Washington, D.C.’s Logan Circle neighborhood.
Jeffrey Carroll, the Metropolitan Police Department’s interim chief, said during a press conference that just before 8 a.m., officers responded to a report of a shooting at the Vida Fitness center at the 1500 block of 15th Street NW.
Police identified the man shot and killed inside the gym as James Stewart, 46, of Northwest Washington. He was the building manager, police said. Mr. Carroll said Dr. Lambert was in an ongoing dispute with his condominium building’s homeowners association management over maintenance issues, which included mold, and had filed a civil case against them. The gym is located in the same building as Dr. Lambert’s condominium.
“We believe it’s related to that,” Mr. Carroll said during the conference.
Police said Dr. Lambert left the gym and returned to his seventh-floor apartment. Dr. Lambert then allegedly fired from his balcony and shot four people: two women and two men. Some of the victims were working across the street at a construction site. Police do not know if Dr. Lambert had a connection with the other four victims.
All four victims were taken to area hospitals. As of the 3 p.m. conference, one was in critical condition and three face non-life-threatening injuries.
While barricaded inside his apartment, Dr. Lambert then fired through the door twice while officers were outside. No officers were hurt, Mr. Carroll said.
MPD hostage negotiators reached Dr. Lambert by phone. During those talks, he broke the gas line in his fireplace and started a fire, police said. The building’s sprinklers helped contain the fire, and D.C. Fire and EMS shut off the building’s gas.
Mr. Carroll said negotiators then heard a single gunshot from inside Dr. Lambert’s apartment, and he stopped speaking. Tactical officers forced their way into his apartment and found him with a self-inflicted gunshot wound. He was pronounced dead at the scene.
A shotgun, a rifle and a handgun were found inside Dr. Lambert’s apartment.
“We’re devastated,” Washington, D.C., Mayor Muriel Bowser said during a Nov. 12 morning press conference. “Someone was killed in our city this morning. A senseless act of gun violence.”
Dr. Lambert served as founder and CEO of MLEM, a healthcare and technology consultancy, according to his website.
Some of his previous roles included chief medical officer and head of product strategy for Advantmed, a healthcare information and services company that helps health plans and provider groups with value-based care; CMO for Curation Health, a risk adjustment platform for value-based care that was acquired in 2024 by Reveleer; and chief medical information officer for Tech Mahindra, a global consulting service and systems integrator company.
Dr. Lambert also previously served as CMIO at New York City-based NYC Health + Hospitals, and held leadership roles at Baltimore-based Johns Hopkins Medicine and Seattle-based University of Washington, his website said.
He was a frequent voice in industry conversations, appearing on several industry podcasts and writing columns for various outlets. The Florida Association of ACOs also listed him as a featured speaker for its 2026 fall conference.
