A Minnesota man who allegedly impersonated an FBI agent and went to a federal prison in New York on Wednesday night claiming to have a court order signed by a judge requiring the release of Luigi Mangione, who is accused of murdering UnitedHealth Group CEO Brian Thompson, has been arrested, according to a new criminal complaint filed Thursday.

Luigi Mangione charged with murder
Luigi Mangione charged with murder

Prosecutors revealed that the 36-year-old man, Mark Anderson, from Mankato, Minnesota, only provided a Minnesota driver's license when he was asked to produce identification by U.S. Bureau of Prisons staff at the Metropolitan Correctional Center in Brooklyn.Mangione is currently being held in the jail without bail for his involvement in the case.

The indictment also states that Anderson claimed the bag he was carrying contained a weapon. The criminal complaint filed by the U.S. Attorney's Office in Brooklyn states that the bag actually contained only a barbecue fork and a round steel blade that resembled a pizza cutter.

"Anderson also displayed and threw numerous documents at Federal Bureau of Prisons officers," wrote an FBI agent who signed the indictment.

"I have reviewed these documents and their contents appear to be related to claims filed against the U.S. Department of Justice," the agent said.

Anderson is scheduled to appear in federal court in Brooklyn on Thursday afternoon on charges of impersonating an FBI agent. Related charges are included in the criminal indictment.

The indictment does not specifically name the prisoner Anderson tried to rescue, but a law enforcement official confirmed that the prisoner was Luigi Mangione.

According to the law enforcement official, Anderson previously went to New York City to seek job opportunities, but failed to do so. He has been working at a local pizza shop recently.

Mangione's incident occurred hours after state prosecutors in Manhattan Supreme Court urged a judge to set his murder trial in July.

Mangione is also charged with multiple counts in Manhattan federal court for allegedly murdering Thompson. Jury selection in the case is scheduled to start in September, two months later than the state court trial. Thompson, a Minnesota resident who was murdered by the suspect who graduated from the University of Pennsylvania, ran UnitedHealth Group, the largest private health insurance company in the United States.

Prosecutors alleged that on the morning of December 4, 2024, Thompson was walking into a hotel in midtown Manhattan to attend an investor event hosted by UnitedHealth Insurance Company, a subsidiary of UnitedHealth Group, when Mangione followed him and shot him, killing him.

Five days after the murder, Mangione was arrested inside a McDonald's in Altoona, Pennsylvania.

Mangione has entered not guilty pleas in two cases in state and federal court.

Federal prosecutors have said they will seek the death penalty if Mangione is found guilty in the federal court case. The judge in the case may rule this week on whether Mangione will face the death penalty.