When Luigi Mangione stepped into a Manhattan federal courtroom shortly after 11am on Friday, his demeanor was less debonair than at other recent court proceedings.The 28-year-old, wearing tan jail scrubs instead of natty menswear, walked with hands behind his back and ankles shackled en route to the defense table. Mangione sat and then studied a piece of paper alongside his attorney.This morning’s proceeding would mark a dramatic twist in Mangione’s legal saga. Mangione, who faces federal and state cases in UnitedHealthcare CEO Brian Thompson’s 4 December 2024 killing, had long maintained a not-guilty stance.But this hearing would change that with one simple sentence.“On the morning of December 4, 2024, I shot Mr Thompson in Manhattan and he died,” he said.He added: “I knew what I was doing was illegal.”The killing of Thompson – gunned down on a Manhattan street – shocked the US and triggered a manhunt that ended with Mangione’s arrest in a Pennsylvania fast-food restaurant. But it also sparked an outpouring of public anger and rage at the actions of the US’s widely reviled for-profit healthcare industry.Many assumed that as Mangione went on trial, so perhaps would an entire industry, as the defense might seek to explain his actions. But the guilty plea – in the federal case against him at least – has ended that prospect.Much of the emotional proceeding, which saw both members of Thompson’s family and some Mangione supporters crying in the gallery, involved Judge Margaret Garnett engaging in the standard questioning judges use to determine whether someone is capable of admitting guilt.Was Mangione ever treated or hospitalized for any kind of mental illness? Was he under the care of a doctor or mental health professional? Had he been treated for any sort of addiction?Mangione answered “no” to all these questions.Garnett asked whether he had taken anything in the last two days and Mangione said yes: trazodone, “for sleeping”.Garnett then queried Mangione on whether anyone had made any promises – or threats – to induce him into pleading guilty. He said no.Then came the moment many observers had long waited for: Mangione would have to describe what happened, in his own words, potentially shedding light on the grisly slaying.Mangione said that “after years of enduring severe pain from a broken back, navigating the obstacles of the health insurance system and witnessing similar experiences of countless others”, he learned that UnitedHealthcare would hold its annual investor conference on 4 December 2024.The specific location wasn’t publicly disclosed, Mangione said, so “I then researched the event online”.“I observed that the annual conference of America’s largest healthcare organization with the stated mission to make health – excuse me – with the stated mission to make the health system work better for everyone, would be attended by company executives, the board of directors and hundreds of investors, not doctors, nurses and patients,” Mangione said.Mangione then told the court that in November of that year, he traveled into Manhattan and engaged in subterfuge to get more information.skip past newsletter promotionafter newsletter promotion“I then emailed UnitedHealthcare leadership posing as an investor at a firm managing over $50bn in assets and requesting information about the conference,” he said. “Unlike my previous interactions with insurers, I received an immediate response within an hour.”Mangione said that he used a 3D printer to forge part of a firearm and affix it with a silencer and magazine.“My travel to New York and email to UnitedHealthcare was with the intent to shoot Brian Thompson,” he said.Both prosecutors and Mangione’s lawyers, under Garnett’s questioning, said they believed there was “sufficient factual evidence” for a plea.“Mr Mangione, how do you now plead to counts one and two of the indictment?” Garnett said, referring to the federal stalking charges against him.“Guilty,” Mangione said plainly, bringing an end to the prospect of a federal trial against him and throwing his state case into potential disarray.After the proceeding wrapped, dozens of journalists convened outside the federal courthouse in downtown Manhattan.“There can be no celebrity in assassination,” prosecutor Jamie McDonald said afterwards, adding that Mangione had “attempted to send a public message through violence”.Mangione’s team announced that they filed paperwork to dismiss the separate state case, which is due to start in September, and in which he faces murder charges. They argued that he could not be charged in Manhattan state court because of New York’s own double-jeopardy law.However, Manhattan prosecutors said their case wasn’t over, saying: “We are prepared to litigate the defense motions” and the team “remains committed to seeking justice for Mr Thompson and his family”.So the Mangione saga is still not over. Not yet.