Luigi Mangione returned to court Friday in a bid to have the most serious charges he faces thrown out of his federal case — as supporters gathered outside of the courthouse for a hearing that could determine whether the potential death penalty remains in play.

The motion to drop two of the four federal charges against Mangione, including the most serious, murder through use of a firearm, would eliminate the potential death penalty if granted.

While the judge did not issue a ruling after attorneys presented arguments on both sides of the issue, she did set a tentative timeline for Mangione's federal trial. No definitive date was set, however.

Judge Margaret Garnett said jury selection could begin in the week of Sept. 8. If it’s a capital case, opening statements would likely be in January 2027. If she grants the defense motion and removes capital charges, opening statements would begin in October.

Earlier this week, federal public defender Paresh Patel joined Mangione's legal team as a special counsel for the Friday hearing. Patel is a Maryland-based appellate attorney and made the defense's arguments against the charges in court.

Patel argued that the federal stalking charges against Mangione don't meet the requirements to justify the more serious charge of murder through use of a firearm because stalking, on its own, isn't a violent crime. 

Assistant U.S. Attorney Jun Xiang, giving oral arguments on behalf of the prosecution, countered that the victim's death is an appropriate element to justify the charge.

UnitedHealthcare CEO Brian Thompson was shot in the back multiple times, on video, by a man prosecutors allege is Mangione.

In one example given by Xiang, he described a gang hit on a house, in which a member tossed a grenade in to kill one person. Additional victims inside died. He argued that the defendant needs to know that his conduct places the victim in fear of reasonable bodily injury.

When the hearing wrapped up around 1:30 p.m., the judge said she would issue a ruling later.

She told the parties to aim for jury selection at the beginning of September, with the trial starting later that fall or early winter, with a January start at the latest.

Separately, federal prosecutors have rejected "meritless" arguments from accused assassin and former Ivy Leaguer Mangione’s legal team claiming Attorney General Pam Bondi has a conflict of interest and should have recused herself due to prior ties to a lobbying firm, ahead of a key hearing in his federal case.

The defense, in previous filings, has accused Bondi of "prejudice" against the defendant and claimed that her former position as a partner at Ballard Partners, a lobbying firm with ties to UnitedHealthcare, should lead to her recusal.

"When Ms. Bondi left Ballard Partners to become the Attorney General in 2025, the very first defendant she personally selected to be executed was the man accused of killing the CEO of her former client," defense attorney Karen Friedman Agnifilo wrote in a December filing.

Prosecutors, however, called her claims "incomplete and misleading."

Bondi no longer works there, they wrote, is not being paid by the firm or its clients and was not influenced by any "corporate interests" when the DOJ decided to seek the death penalty against Mangione if he is convicted.

Although his lawyers have dropped their motion to suppress statements he made to police before and after his arrest at a Pennsylvania McDonald's, the defense is still hoping to suppress damning evidence recovered from Mangione's backpack without a search warrant.

Federal prosecutors have countered that the suspected murder weapon and allegedly incriminating journals inside would have inevitably been discovered later — even if Altoona police hadn't searched it at the scene.

The judge said she did not see the need for an evidentiary hearing that the defense requested on the matter.

Federal prosecutors had opposed the idea of holding one.

Legal experts have said police do not typically need one when they search a bag as part of the arrest process, and prosecutors said everything in the bag would have been inevitably obtained later when they obtained their search warrants.

Surveillance video shows a man approach the 50-year-old Thompson from behind and gun him down outside a Manhattan hotel that was supposed to host a shareholder conference later that morning.

The Minnesota resident was a married father of two.

Fox News' Brendan McDonald contributed to this report.