A psychiatric defense may be Luigi Mangione’s best argument in state murder trial, experts say. Here’s why

By Kara Scannell, Nicki Brown, CNN

New York (CNN) — The day after Luigi Mangione was arrested in connection with the December 2024 killing of a health insurance executive, a former prosecutor suggested his best defense might be claiming a form of insanity.

“There might be a not guilty by reason of insanity defense that they’re going to be thinking about, because the evidence is going to be so overwhelming that he did what he did,” attorney Karen Friedman Agnifilo, then a CNN legal analyst, told Anderson Cooper.

“You have someone who was a valedictorian of his class, he was brilliant his whole life, he comes from this great family. I mean, something changed, right? Significantly, something changed,” she said.

Three days later, CNN reported Mangione hired Friedman Agnifilo, a longtime member of the Manhattan District Attorney’s office, which is prosecuting the 28-year-old on murder and weapons charges for allegedly fatally shooting UnitedHealthcare Chief Executive Brian Thompson. Mangione has pleaded not guilty to the state charges, as well as federal stalking charges.

It is not clear whether Mangione will invoke an affirmative mental health defense – where a defendant admits to the alleged conduct but argues they should not be held fully liable due to psychiatric reasons – when his state trial begins in September.

But Friedman Agnifilo’s comments offer a window into what may now be playing out behind the scenes:

Last August, in a publicly filed letter, Mangione’s lawyers asked the judge for more time before informing the prosecution of their decision on a mental health defense if they planned to pursue one. There have been no subsequent public mentions of the issue. A court hearing earlier this month was sealed at the defense’s request.

Mangione is due to appear in state court this week.

Lawyers and forensic psychologists told CNN a mental health defense, while challenging, is likely Mangione’s best bet given the strength of the evidence against him. In a key ruling last month, the judge cleared the way for prosecutors to present the alleged murder weapon found in his backpack and writings expressing animosity toward the healthcare industry and a desire to “wack (sic) the CEO.”

A psychiatric defense could also offer a path for Mangione’s lawyers to try to make him sympathetic to the jury.

“There’s absolutely going to be a mental defense in this case,” predicted Kris Mohandie – a forensic psychologist who has worked with law enforcement for over three decades – pointing to what he called a “significant change” in Mangione’s behavior before Thompson’s killing.

Mangione’s arrest shocked people who knew him, while others looked for clues that might explain his alleged motive. Mangione underwent back surgery and posted an X-ray of his postsurgery spine online. In the months before the shooting, Mangione’s once active online presence stopped, and his mother filed a missing persons’ report.

“Jurors always want to understand why, and they want it explained, and this will help explain it,” Mohandie, who is not involved in the Mangione case, said of a psychiatric defense. “It will also, in the process, I believe, humanize what is a very predatory attack on this man.”

“They need to do it, and it will render him more sympathetic potentially, if done correctly,” he said.

Mangione’s lawyers have not responded to CNN’s requests for comment, but they have previously declined to comment on defense strategy.

A representative for the district attorney’s office declined to comment.

Extreme emotional disturbance

Thompson’s killing unleashed a firestorm of ire against the US healthcare industry and generated a wave of support for Mangione. Supporters lined up for a chance to see him at court hearings; donors have contributed more than $1.5 million toward his defense. Law enforcement officials have condemned the support for him as a shocking “celebration” of a cold-blooded murder.

A mental health defense could be a way for Mangione’s lawyers to tap into a juror’s potential frustration with the healthcare industry, Mohandie said.

“This gets you the ability to talk about a lot of this stuff if you introduce his thought process about it,” Mohandie said.

On the other hand, such a defense can give prosecutors more information to work with, lawyers say, allowing them to subpoena medical records and interview a defendant’s family members.

“It opens up the door to different types of evidence that would otherwise not be relevant,” said Gary Galperin, a former prosecutor who cowrote a study on mental health defenses.

“You can speak to employees, roommates, all the persons who might have had contact with the accused,” Galperin said.

“Psychiatric defenses are often defenses of last resort,” he added. They are rarely successful because a true insanity defense requires the accused to have not known what they were doing was wrong.

Another affirmative defense available to New York criminal defendants is that they were acting under the influence of an extreme emotional disturbance spurred by an event that made them temporarily lose control, legal experts said. If a jury finds a defendant has proved by a preponderance of evidence he acted because of an extreme emotional disturbance, or EED, the crime is reduced from murder to manslaughter, which carries far less prison time.

“It’s not a get out free (card),” Hermann Walz, an adjunct professor at John Jay College of Criminal Justice, told CNN. “It’s basically just saying, I’m reducing the crime.”

The EED defense is often used in cases where a defendant acts in the heat of the moment, such as finding their spouse cheating on them. It can also be put forward in cases where a person acts upon emotions that have been festering for a long time, such as abused women who kill their attackers after a “long-standing buildup of trauma,” said criminal defense attorney Earl Ward.

Still, some defendants have successfully applied an EED defense in cases that differ from these typical scenarios, including when the defendant was under the influence of drugs or acted based upon a mistaken belief.

Ward effectively presented the defense when he represented Gigi Jordan, a former pharmaceutical executive accused of killing her 8-year-old son Jude Mirra with a lethal drug concoction in a luxury Manhattan hotel.

“It wasn’t a question of if she gave her son these drugs – she clearly did,” Ward told CNN this month. “It really was about her mental state and what caused her to do something so extreme.”

During the 2014 trial, Jordan took the stand and portrayed her actions as a mercy killing, telling the jury she believed her ex-husband was going to kill her, which would have left Jude in the custody of a relative she believed had abused him.

The relative denied the allegations, according to CNN affiliate WCBS, and prosecutors said there was no evidence the boy was ever abused.

“Even if her belief was mistaken, as long as she reasonably believed that the child was in danger, she acted under extreme emotional disturbance,” Ward said.

The jury accepted Jordan’s claim and convicted her of manslaughter, the lesser charge to second-degree murder. At sentencing, she faced between 5 and 25 years in prison – a range far less than the 15 years to life in prison she would have faced if she were convicted of the murder charge.

In another high-profile case, Christopher Thomas stood trial for the so-called 1984 “Palm Sunday Massacre,” where he shot and killed eight children and two women in a home in Brooklyn, The New York Times reported at the time.

At trial, Thomas’s attorneys argued he was addicted to cocaine and had become infuriated by his wife’s alleged infidelity, leading him to commit the rampage under an extreme emotional disturbance, according to the Times. The jury agreed and convicted Thomas of manslaughter instead of murder, with some jurors emphasizing the role of his addiction.

“He had been free-basing for two years,” one juror told the Times after the verdict, referring to a method of taking cocaine. ”That would make anybody emotionally disturbed.”

Thomas was released from prison in 2018 after serving roughly 32 years, according to CNN affiliate Spectrum News NY1.

Mangione’s alleged statements could undermine mental health defense

If Mangione ultimately mounts a psychiatric defense, it could be complicated by his own alleged writings and behavior before and after the shooting, which experts say provide insight into his state of mind.

Authorities allege Mangione wore a hoodie to disguise himself, used a firearm silencer and had an escape plan to flee the city prior to his arrest five days later nearly 300 miles away in Altoona, Pennsylvania – behavior lawyers said would undercut any suggestion he didn’t know what he was doing was wrong.

Normally, someone who acted from EED “would be so distraught after the killing that you would want to talk about it. You would not want to flee. You wouldn’t try to hide your guilt,” Galperin, the former prosecutor, said. “What (Mangione) did after the crime seems to negate the psychiatric defense.”

Authorities also found a notebook in Mangione’s backpack containing handwritten entries that expressed frustration with the healthcare industry and an intent to carry out an attack, according to court filings. Prosecutors are expected to use the writings – some of which are dated months before the killing – to argue it shows Mangione’s “unambiguous” intent and motive to target the CEO of the country’s largest health insurance company.

“His journal entries will document that known process we see in people that actually pose a genuine threat, and it will underscore the predatory nature that was cooking all this time,” said Mohandie, the forensic psychologist.

“Prosecutors will grab a hold of that, but good defense attorneys and mental health people will be mining it to see if there’s any indicator of psychosis, delusion, or just a guy that is so depressed or disturbed that they can use that maybe for a potential defense,” Mohandie added.

“If you ask me whether it’s legitimate or not, I’m going to say I don’t know enough yet,” he said.

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CNN’s Eric Levenson contributed to this report.