Prosecutors in Luigi Mangione’s state trial are defending the search of his backpack and urging a judge to allow the evidence in his upcoming murder trial, despite the defense arguing the search was unconstitutional.

Prosecutors argued that Mangione’s bid to suppress evidence taken from his backpack and specific statements he made to police should be denied by the court because Pennsylvania authorities acted "reasonably" during the search, according to court documents obtained by Fox News.

The filing comes after a three-week hearing in 2025, in which Mangione’s defense team argued the alleged murder weapon, handwritten notes and additional items seized from the accused killer’s backpack were inadmissible because they violated his constitutional rights. 

However, the Manhattan district attorney’s office is insisting the Altoona authorities "responded to this unexpected and alarming situation reasonably," when they searched Mangione’s backpack and arrested him inside the rural McDonald’s, according to the court filing.

"Altoona officers obtained a search warrant for the backpack, thereby establishing an independent source for recovering the backpack's contents," assistant district attorney Joel Seidemann wrote.

The prosecution also pointed to the defense’s claim that Altoona officers did not comply with New York’s search-and-seizure law, insisting that the Pennsylvania authorities were "unfamiliar" with the guidelines of another state.

"Nor could they be expected to familiarize themselves with that body of law in advance of the defendant’s arrival, which they had no way of anticipating," Seidemann wrote. 

Mangione has pleaded not guilty to both state and federal charges stemming from the 2024 shooting death of UnitedHealthcare CEO Brian Thompson in midtown Manhattan.

He was arrested days later at an Altoona McDonald’s and extradited to New York City, where he remains in custody awaiting trial.  

Judge Gregory Carro expects to issue a decision regarding the evidence by May 18, according to WABC. 

Mangione’s state trial is set to begin on June 8. 

Mangione's defense team did not immediately respond to Fox News Digital's request for comment.