Luigi Mangione Federal Plea Deal Has Angered NY D.A., Says It's Obstruction of Justice

Prosecutors in the Manhattan District Attorney's Office have been pissed off at Luigi Mangione's team for trying to sabotage its case by striking a plea bargain with the feds.

The judge in the state case just unsealed docs, one of which was a letter to the court, dated July 2, 2026, in which Assistant D.A. Joel Seidemann wrote that his office had heard rumblings of a plea bargain in the federal case.

As TMZ reported, if Luigi were to plead guilty to murder in the federal case, the state case would be dismissed based on double jeopardy.

Seidemann groused it would not be fair to the State of New York for the feds to agree to a plea bargain. Seidemann says the State's trial is supposed to start next month, before the January start date for Mangione's federal trial ... and he says that's the way it should be, because the law says whoever arrests a defendant should go first, and he was arrested by New York authorities.

Seidemann is accusing Luigi's legal team of obstructing justice by trying to torpedo the State case with a federal plea bargain.

As we reported, the defense is set to cop a plea Friday, and that would open the door to a sentencing hearing where Luigi and co. could present mitigating evidence -- i.e., his alleged distorted mental state fueled by his anger over corporate greed in the health care system.