MedPage Today reports that police named emergency physician Matt Lambert as the gunman in a mass shooting around 8 a.m. on 12 November 2026 in Washington, D.C.'s Logan Circle, saying he fatally shot a man at a gym, left another critically injured, shot others, then barricaded himself and killed himself. Police cited a dispute with his building's homeowners association, and an X account apparently tied to Lambert posted a manifesto that morning stating, "My manifesto is an engineering report."