DC gunman made eerie comment about victim’s routine before shooting — and invoked slogan inscribed on Luigi Mangione’s bullets

A Washington, DC, doctor shot and killed his building manager at a gym, injured four other people and later died by suicide after an hour-long police standoff. The attack followed a dispute over mould and maintenance in his penthouse, and earlier comments about the manager’s routine and a slogan associated with Luigi Mangione have drawn attention to what he said before the shooting.

Police said the dispute involved the building’s homeowners’ association and maintenance issues. The doctor, Matt Lambert, had sued the association over mould and other problems; in past conversations, he described the dispute as “psychological warfare” and referred to “delay, deny, defend”, a phrase linked to Mangione’s bullets. He also posted about the dispute on X shortly before the attack, citing a report on suspected microbial growth and water intrusion.