NEW YORK (AP) — Luigi Mangione is due back in court on Tuesday for the second day of a hearing in his bid to bar New York prosecutors from using evidence that they say links him to last year’s killing of UnitedHealthcare CEO Brian Thompson.

The pretrial hearing in Mangione’s state murder case kicked off Monday with prosecutors playing surveillance videos of the Dec. 4, 2024, killing and security footage of his arrest five days later at a McDonald’s in Pennsylvania.

Mangione, 27, gripped a pen in his right hand, making a fist at times, as prosecutors played the audio of a 911 call from a McDonald’s manager relaying concerns from customers that Mangione looked like the suspect in Thompson’s death.

Mangione’s lawyers are asking Judge Gregory Carro to block prosecutors from showing or telling jurors about items seized from his backpack during his arrest, including a 9 mm handgun that prosecutors say matches the one used in the killing and a notebook in which they say Mangione described his intent to “wack” a health insurance executive.

The defense contends the items should be excluded because police didn’t have a warrant to search his backpack. They also want to suppress some statements Mangione made to law enforcement personnel, such as allegedly giving a false name, because officers started asking questions before telling him he had a right to remain silent.

Mangione, the Ivy League-educated scion of a wealthy Maryland family, has pleaded not guilty to state and federal murder charges. The state charges carry the possibility of life in prison, while federal prosecutors are seeking the death penalty. Neither trial has been scheduled. The next hearing in the federal case is scheduled for Jan. 9.

Mangione’s lawyers want to bar evidence from both cases, but this week’s hearing pertains only to the state case.

Five witnesses testified on Monday, including a Pennsylvania prison officer who said Mangione told him that at the time of his arrest he had a backpack with foreign currency and a 3D-printed pistol.

Another prison officer said his superintendent told him Mangione was being held under constant watch because the facility “did not want an Epstein-style situation,” referring to Jeffrey Epstein’s 2019 jail suicide.

More law enforcement officers are expected to take the witness stand on Tuesday.

Surveillance video showed a masked gunman shooting Thompson from behind as the executive walked to a midtown Manhattan hotel for his company’s annual investor conference. Prosecutors say “delay,” “deny” and “depose” were written on the ammunition, mimicking a phrase used to describe how insurers avoid paying claims.

Mangione was arrested as he ate breakfast at a McDonald’s in Altoona, Pennsylvania, about 230 miles (about 370 kilometers) west of Manhattan after the restaurant’s manager told a 911 dispatcher, “I have a customer here that some other customers were suspicious of — that he looks like the CEO shooter from New York.”

The manager told the dispatcher that she searched online for photos of the suspect that police disseminated. But, as Mangione sat in the restaurant, she said she could only see his eyebrows because he had a beanie pulled down close to his eyes and was wearing a medical face mask.

On Monday, a few dozen Mangione supporters watched the hearing from the back of the courtroom.

One wore a green T-shirt that said: “Without a warrant, it’s not a search, it’s a violation.” Another woman held a doll of the Luigi video game character and had a smaller figurine of him clipped to her purse.

Court officials say the hearing could take more than a week.

STOCKTON, Calif. (AP) — Authorities in California appealed to the public for tips, cellphone video, witness accounts and even rumors as they searched Sunday for a suspect in the killing of three children and an adult during a mass shooting at a child’s birthday party.

Someone opened fire at a banquet hall in Stockton where 100 people or more had gathered on Saturday, San Joaquin County Sheriff Patrick Withrow told reporters. He said detectives believe the gunfire continued outside and there may have been multiple shooters.

Withrow said the deceased were ages 8, 9, 14 and 21. Eleven people were also wounded, with at least one in critical condition, he said. No one was in custody by Sunday evening, and the sheriff urged anyone with information to contact his office.

“This is a time for our community to show that we will not put up with this type of behavior, when people will just walk in and kill children,” Withrow said during a Sunday media briefing. “And so if you know anything about this, you have to come forward and tell us what you know. If not, you just become complacent and think this is acceptable behavior.”

Sheriff’s spokesperson Heather Brent said earlier that investigators believe it was a “targeted incident.” Officials did not elaborate on why authorities believe it was intentional or who might have been targeted.

Roscoe Brown said the party was in honor of his brother’s granddaughter, who turned 2 years old and was uninjured. Brown, who works for the city of Stockton’s Office of Violence Prevention, was in Arizona when he learned about the shooting and drove straight to the scene. He said a niece and nephew of his were shot, and he knows several other victims. He didn’t have information about their conditions.

“Who would come and do that to some kids, you know?” Brown told The Associated Press following a vigil organized by faith leaders to honor the dead and pray for the wounded. “You can’t shoot up a party. That’s senseless. A kid’s party, at that.”

The shooting occurred just before 6 p.m. Saturday inside the hall, which shares a parking lot with other businesses in the city of 320,000 residents about 80 miles (130 kilometers) east of San Francisco.

“This was a birthday party for a young child, and the fact that this happened is absolutely heartbreaking,” Brent told reporters. She said investigators would welcome any information, “even rumors.”

District Attorney Ron Freitas urged the shooter to “turn yourself in immediately.”

Hours after the shooting, the Stockton Police Department arrested five people, including a juvenile, on weapons and gang-related charges. There was no indication that the arrests were connected to the killings at the banquet hall, the sheriff said.

Mayor Christina Fugazi told reporters that the 8-year-old victim attended a local school and had a parent who worked for the Stockton Unified School District. The mayor said counselors would be available this week at city schools.

Community leaders expressed anguish over the loss of victims so young.

“They should be writing their Christmas lists right now. Their parents should be out shopping for them for Christmas. And to think that their lives are over. I can’t even begin to imagine what these families are going through. Breaks my heart,” Fugazi said on Sunday.

In 2024, Stockton had many more homicides — 54 — than other California cities of similar size, but the rate was down through October of this year, according to city data.

Fugazi on Saturday recalled a shooting several years ago in which “seven people were gunned down” in the city.

Withrow said he cut his family’s Thanksgiving celebration short and drove more than eight hours from Oregon to the shooting scene.

“I put down my grandbabies, to come hunt down these animals who took somebody else’s babies away from them,” the sheriff said.