ALTOONA, Pa. (AP) — The gun found on the suspect in the killing of United Healthcare’s CEO matched shell casings found at the site of the shooting, New York City’s police commissioner said Wednesday.

Suspect Luigi Mangione 's fingerprints also matched a water bottle and a snack bar wrapper that police found near the scene in midtown Manhattan, Commissioner Jessica Tisch said at an unrelated news conference. Police had said earlier that they believed the gunman bought the items at a nearby coffee shop while awaiting his target.

Mangione, 26, was charged with murder in last week's shooting of Brian Thompson, who led the United States' largest medical insurance company.

Authorities have said that writings found in Mangione's possession hinted at a hatred of corporate greed.

They’ve recovered a spiral notebook that Mangione kept, along with a three-page, handwritten letter found when he was arrested Monday in Pennsylvania, a law enforcement official said Wednesday. Police have not disclosed what was in the notebook.

The letter teased the possibility that clues to the attack — “some straggling notes and To Do lists that illuminate the gist of it” — could be found in the notebook, the law enforcement official said. The official wasn’t authorized to disclose information about the investigation and spoke to The Associated Press on condition of anonymity.

The New York Police Department's top detective, Joseph Kenny, told CBS New York on Tuesday that the motive might have been related to an accident that sent Mangione to an emergency room on July 4, 2023.

A law enforcement bulletin obtained by the AP earlier this week said the letter disdained corporate greed and what Mangione called “parasitic” health insurance companies. The prep school and Ivy League graduate wrote that the U.S. has the most expensive health care system in the world and that major corporations' profits continue to rise while life expectancy doesn't, according to the bulletin.

In his first public words since his arrest, Mangione shouted about an "insult to the intelligence of the American people" on his way into court Tuesday. Mangione remained jailed without bail Wednesday in Pennsylvania, where he was initially charged with gun and forgery offenses.

Manhattan prosecutors were working to bring him to New York. At a brief hearing Tuesday in Pennsylvania, defense lawyer Thomas Dickey said Mangione will not waive extradition and instead wants a hearing on the issue.

“You can’t rush to judgment in this case or any case,” Dickey said afterward. “He’s presumed innocent. Let’s not forget that.”

Mangione was arrested in Altoona, about 230 miles (about 370 kilometers) west of New York City, after a McDonald’s customer recognized him and notified an employee, authorities said.

New York police officials have said Mangione was carrying a gun like the one used to kill Thompson and the same fake ID the suspected shooter had used to check into a New York hostel, along with a passport and other fraudulent IDs.

Thompson, 50, was killed Dec. 4 as he walked alone to a Manhattan hotel for an investor conference. From surveillance video, New York investigators determined the shooter quickly fled the city, likely by bus.

His movements afterward are unclear, but authorities believe he took steps to stay off the radar. Prosecutors said at his Pennsylvania hearing this week that when arrested, he had bags for his cellphone and laptop that prevent such devices from transmitting signals that authorities can use to track them.

Mangione, a grandson of a well-known Maryland real estate developer and philanthropist, had a graduate degree in computer science and worked for a time at a car-buying website. During the first half of 2022, he bunked at a “co-living” space in Hawaii, where those who knew him said he suffered from severe and sometimes debilitating back pain.

His relatives have said in a statement that they are was “shocked and devastated" at his arrest.

___

Sisak reported from New York. Associated Press writer Jennifer Peltz contributed.

Suspect Luigi Mangione is taken into the Blair County Courthouse on Tuesday, Dec. 10, 2024, in Hollidaysburg, Pa. (Benjamin B. Braun/Pittsburgh Post-Gazette via AP)

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Suspect Luigi Mangione is taken into the Blair County Courthouse on Tuesday, Dec. 10, 2024, in Hollidaysburg, Pa. (Benjamin B. Braun/Pittsburgh Post-Gazette via AP)

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This booking photo provided by Pennsylvania Department of Corrections on Tuesday, Dec. 10, 2024, shows shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (Pennsylvania Department of Corrections via AP)

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This booking photo provided by Pennsylvania Department of Corrections on Tuesday, Dec. 10, 2024, shows shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (Pennsylvania Department of Corrections via AP)

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Suspect Luigi Mangione is taken into the Blair County Courthouse on Tuesday, Dec. 10, 2024, in Hollidaysburg, Pa. (Janet Klingbeil via AP)

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Luigi Nicholas Mangione is escorted into Blair County Courthouse, Tuesday, Dec. 10, 2024, in Hollidaysburg, Pa. (AP Photo/Gary M. Baranec)

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Gov. Josh Shapiro, center, speaks during a press conference regarding the arrest of suspect Luigi Mangione, Monday, Dec. 9, 2024, in Hollidaysburg, Pa., in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (AP Photo/Ted Shaffrey)

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This photo, provided by the Hawaii Dept. of Land and Natural Resources, shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson, receiving a citation for failing to observe a posted closed-area sign, in Honolulu, Sunday, Nov. 12, 2023. (Hawaii Dept. of Land and Natural Resources via AP)

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This combo image release by Pennsylvania State Police shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson, at a McDonald's in Altoona, Pa., Monday, Dec. 9, 2024. (Pennsylvania State Police via AP)

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This photo provided by Pennsylvania State Police shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson, at the police station in Altoona, Pa., on Monday, Dec. 9, 2024. (Pennsylvania State Police via AP)

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This photo provided by Pennsylvania State Police shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson, at the police station in Altoona, Pa., on Monday, Dec. 9, 2024. (Pennsylvania State Police via AP)

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This booking photo released Monday, Dec. 9, 2024, by the Pennsylvania Department of Corrections shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (Pennsylvania Department of Corrections via AP)

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Suspect Luigi Mangione is taken into the Blair County Courthouse on Tuesday, Dec. 10, 2024, in Hollidaysburg, Pa. (Janet Klingbeil via AP)

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