Luigi Mangione's attorneys plan to mount a psychiatric defense when the accused killer of UnitedHealthcare CEO Brian Thompson faces trial in New York state court, his legal team disclosed during a recent hearing in Manhattan.
The defense filed notice under New York Criminal Procedure Law Section 250.10, which requires the defense to alert prosecutors in advance if it intends to present psychiatric evidence at trial. The filing does not specify whether Mangione's lawyers will pursue a full insanity defense or a narrower argument that his mental state at the time of the shooting negated the intent required for first-degree murder.
Mangione, 26, stands charged with first-degree murder, two counts of second-degree murder, and additional weapons and forgery charges in connection with the December 4, 2024, fatal shooting of Thompson outside a Midtown Manhattan hotel. He has pleaded not guilty. If convicted on the top count, he faces a mandatory sentence of life without parole.
A Section 250.10 notice is a procedural step, not a diagnosis. It tells the prosecution that the defense may call psychiatrists or psychologists to testify about the defendant's mental condition. New York law draws a sharp line between two possible uses of that testimony.
The first is a classic insanity defense under New York Penal Law Section 40.15. To prevail, the defense would need to show that Mangione, at the time of the shooting, lacked substantial capacity to know or appreciate the nature and consequences of his conduct, or that his conduct was wrong. The burden falls on the defense to prove insanity by a preponderance of the evidence.
The second possibility is a so-called "diminished capacity" argument. Under this theory, psychiatric evidence would not excuse the killing but would challenge whether Mangione formed the specific intent required for first-degree murder. If a jury accepted that argument, it could convict on a lesser charge rather than acquit outright.
The defense has not publicly stated which path it will take. CBS News New York reported on the hearing and the psychiatric notice filing, but defense attorneys did not elaborate on the clinical basis for the strategy.
Mangione also faces separate federal charges, including murder through the use of a firearm and stalking. Federal prosecutors have indicated they intend to seek the death penalty. The federal and state cases are proceeding on parallel tracks, and the state trial is currently expected to move forward first.
During the Manhattan hearing, the court addressed scheduling and pretrial motions. Judge Gregory Carro is overseeing the state case. No firm trial date has been set, but both sides have signaled they expect proceedings to move into late 2025.
The parallel prosecution creates a layered legal landscape for Mangione's defense team. A psychiatric strategy in state court could carry implications for the federal case, where mental-health defenses operate under different standards. Federal law uses a narrower insanity test that requires the defense to prove, by clear and convincing evidence, that the defendant was unable to appreciate the nature and quality or wrongfulness of his acts due to a severe mental disease or defect.
Thompson, 50, was shot and killed on the morning of December 4, 2024, outside the New York Hilton Midtown, where UnitedHealthcare's parent company was holding an investor conference. Surveillance footage captured a masked gunman approaching Thompson from behind and firing multiple rounds before fleeing on foot and then by bicycle.
The shooting triggered a five-day manhunt that ended when Mangione was recognized and detained at a McDonald's in Altoona, Pennsylvania, on December 9. At the time of his arrest, authorities said he was carrying a firearm, a suppressor, a fake ID, and a handwritten document that expressed grievances against the health insurance industry. Mangione was initially charged in Pennsylvania before being extradited to New York.
Prosecutors in Manhattan allege the killing was premeditated and targeted. The first-degree murder charge rests on the theory that Thompson was killed in furtherance of an act of terrorism, a legal classification that carries the mandatory life-without-parole sentence. The two second-degree murder counts allege intentional killing and depraved indifference to human life.
Psychiatric defenses in New York carry heavy skepticism from juries and significant procedural burdens for the defense. The state reformed its insanity laws after John Hinckley Jr.'s 1982 acquittal in the attempted assassination of President Reagan, tightening the standard and shifting the burden of proof to the defendant.
Filing the Section 250.10 notice also opens the door for the prosecution to have Mangione examined by its own psychiatric experts. If the defense puts his mental state at issue, prosecutors can retain clinicians to conduct an independent evaluation and present competing testimony at trial.
Defense attorney Karen Friedman Agnifilo, who is part of Mangione's legal team, has experience in high-profile Manhattan cases. She previously served as the chief assistant district attorney in the Manhattan DA's office before entering private practice. Mangione's lead counsel, Marc Agnifilo, has handled complex federal and state criminal matters.
The defense team has not disclosed whether Mangione has undergone psychiatric evaluation, who conducted any such evaluation, or what diagnoses, if any, have been reached. Those details would likely emerge during pretrial discovery and expert-disclosure deadlines set by the court.
The psychiatric notice forces the Manhattan District Attorney's office to build a rebuttal case on Mangione's mental state. Prosecutors will need to retain their own forensic psychiatrists, review any defense expert reports once disclosed, and prepare to argue that Mangione acted with full awareness and deliberate intent.
If the defense pursues a pure insanity theory, prosecutors can point to the alleged planning involved in the shooting: the travel to New York, the acquisition of a weapon and suppressor, the use of a disguise, and the written document found at the time of arrest. Premeditation and methodical execution are typically powerful counterarguments to claims that a defendant could not appreciate the nature of his actions.
If the defense instead uses psychiatric testimony only to challenge specific intent, the stakes shift. A jury could still convict on second-degree murder or manslaughter, but the most severe charge and its mandatory life sentence could fall away.
Investigators have not publicly confirmed a motive beyond the written document recovered during the arrest. Authorities have not said whether Mangione had any prior diagnosed mental health conditions, whether he sought treatment before the shooting, or whether any prescriptions or medical records factor into the defense theory.
The court has not yet ruled on key pretrial issues, including the admissibility of the document found on Mangione and whether statements he made to Pennsylvania law enforcement will be suppressed. Those rulings could shape the contours of both the prosecution's case and the psychiatric defense.
No date has been set for the next major hearing. The federal case timeline also remains fluid, with prosecutors and defense counsel still working through early procedural stages.
A man is dead on a Manhattan sidewalk, and the legal system now faces the task of determining not just what happened, but what was going on inside the mind of the man accused of pulling the trigger. That question will test whether psychiatric defenses serve justice or simply soften accountability.
