Why September is a crucial month in the Luigi Mangione case
Mangione, 27, faces charges in both New York state and federal courts. In state court, he is charged with murder as an act of terrorism
By Callum Wells
September is a crucial month for Luigi Mangione, the man accused of murdering UnitedHealthcare CEO Brian Thompson.
Mangione, 27, faces charges in both New York state and federal courts. In state court, he is charged with murder as an act of terrorism – an offence that carries a life sentence. In federal court, prosecutors are seeking the death penalty. Key decisions in both cases are set to unfold this month.
A digital billboard truck circled Manhattan federal court during his April 2025 arraignment, displaying the words “End the death penalty now”.
The death penalty
In federal court, Mangione’s legal team, led by Karen Friedman Agnifilo, must file a motion by 19 September challenging the constitutionality of the death penalty.
Mangione’s court-appointed death penalty lawyer, Avraham Moskowitz, said in June that the defence had been preparing this filing since April, when Attorney General Pam Bondi directed prosecutors to pursue capital punishment.
Prosecutors argue that there are “aggravating factors” that make Thompson’s killing eligible for the death penalty, including “substantial planning,” “victim impact” and the risk to others.
Surveillance footage from an investor conference shows Thompson being shot at close range. Prosecutors noted that a female bystander was standing “only a few feet from Thompson” at the time, with others “in close proximity”.
US District Judge Margaret Garnett has yet to rule on a defence request that prosecutors disclose the “theories and facts” behind these aggravating factors. Prosecutors say they have already provided ample material – nearly seven terabytes by the defence’s estimate – and are not required to reveal further details until closer to trial.
Who tries Mangione first – state or federal?
A key unresolved question is which court will try Mangione first.
At an April arraignment, federal prosecutor Dominic Gentile said he expected the state trial to proceed first, as originally agreed by Manhattan District Attorney Alvin Bragg and then–US Attorney Damian Williams.
But Mangione’s lawyers want the federal case to take precedence and have asked both judges to delay the state proceedings indefinitely. Garnett has indicated she may set a “firm” 2026 trial date when the parties reconvene in December.
The state case is further advanced and less complex, given that the death penalty is not an option. Lead state prosecutor Joel Seidemann has argued that Bragg’s case should therefore go first.
The order could become clearer at Mangione’s next state court appearance on 16 September, when New York Supreme Court Justice Gregory Carro may set a trial date or yield to federal proceedings.
New York’s terrorism charge
Mangione’s defence is also challenging the state’s murder-as-terrorism charge. In filings submitted in May, they argued the law is meant for crimes designed to intimidate larger communities, saying “Mangione is no terrorist”.
They further claim that dual prosecutions in state and federal court “violate the double jeopardy clause and Mr. Mangione’s constitutional rights,” since arguments in one case could be used against him in the other.
The defence has also sought to exclude evidence obtained during Mangione’s 9 December arrest at a McDonald’s in Pennsylvania, calling the search improper. Items seized included a homemade “ghost gun” allegedly matching ballistics from the crime scene and a handwritten “manifesto”.
In June, Seidemann countered that the evidence was properly obtained and that Thompson’s killing – as CEO of one of the country’s largest health insurance companies – was clearly terrorism.
In recovered writings, prosecutors said Mangione “rejoiced that he could commit this assassination at the investor conference: he explained that the best way ‘to rebel against the deadly, greed fuelled health insurance cartel’ was to ‘wack [sic] the CEO’ at such a conference”.
Carro is expected to rule on the defence’s dismissal and evidence suppression motions at the 16 September hearing.
Psychiatric defence – still possible
Another issue is whether the defence will be permitted to pursue a psychiatric defence, despite missing the 25 August deadline.
They have asked for an indefinite extension, again citing their belief that the federal trial should go first. Seidemann, however, has urged Carro to enforce the deadline and bar psychiatric evidence.
Prosecutors pointed to the recent state conviction of Hadi Matar in the attempted murder of author Salman Rushdie, noting he was tried in state court before facing federal charges.
Legal experts told Business Insider that Mangione’s strongest chance of avoiding life in prison or execution may be an extreme emotional disturbance defence, which could reduce his sentence in either court.
HIPAA records dispute
Finally, on 19 September, Carro may also rule on whether Mangione’s 120-page Aetna healthcare history – disclosed by mistake – can be used.
The defence argues for suppression and a full evidentiary hearing, while prosecutors insist there was no ethical breach.
Online fashion giant SHEIN recently launched an investigation after Mangione appeared in a now-deleted site listing.
He is currently working as an orderly, taking on cleaning responsibilities, at Brooklyn’s Metropolitan Detention Center.