Luigi Mangione, the accused killer of a UnitedHealthcare CEO, pleaded guilty Friday to two federal counts of stalking resulting in death, according to The Associated Press.“I shot Mr. Thompson and he died,” Mangione reportedly said in court. “I knew what I was doing was illegal.”Such a plea appears likely to throw his New York state murder trial, scheduled to begin Sept. 8, into doubt as it is expected his attorneys will argue double-jeopardy protections should come into play. Generally, a person cannot be charged twice for the same act, although legal experts say that determining which charges are duplicative can be quite complicated. Mangione has alleged that allowing both the state and federal cases against him to proceed violates his rights. The federal trial had been scheduled to begin Jan. 5, 2027, with Mangione facing life behind bars.Now, he will face sentencing on the two counts on Dec. 18, CNN reported.The 28-year-old is accused of shooting and killing CEO Brian Thompson in a brazen act of violence on a New York City street in December 2024. Thompson’s death sparked a massive search, leading to Mangione’s capture five days later at a Pennsylvania McDonald’s where he was having breakfast. Police say they found a backpack full of evidence — including flash drives, a firearm, a homemade silencer and a red notebook supposedly referencing the crime — but errors in processing prompted New York Supreme Court Judge Gregory Carro to bar certain items from the state trial.Members of Thompson’s family appeared in federal court on Friday to witness the plea, CNN reported.This is a developing story. Please check back for updates.