Luigi Mangione is due to appear in federal court on Friday as plea negotiations continue over charges linked to the killing of UnitedHealthcare CEO Brian Thompson.

CNN citing sources reported that Mangione could plead guilty as soon as today, although negotiations remain fluid and no agreement is final until it is announced in court.

The unexpected appearance was requested earlier this week by both prosecutors and Mangione's lawyers without a public explanation.

Mangione, 28, has pleaded not guilty to state and federal charges connected to Thompson's fatal shooting in New York City in December 2024.

He faces federal stalking charges in the Southern District of New York. Separately, state prosecutors have charged him with second-degree murder and weapons offences.

Any federal plea agreement would require approval from US District Judge Margaret Garnett.

A guilty plea could also raise questions about the separate state prosecution.

Mangione's lawyers have sought to challenge that case on double jeopardy grounds under New York law, although the immediate effect of any federal plea remains unclear.

Mangione's state murder trial is scheduled to begin with jury selection on September 8.