News world:The gun CEO killing suspect Luigi Mangione had upon arrest matches shell casings from the crime scene, police say

The 3D-printed gun that health care CEO killing suspect Luigi Mangione had when he was arrested this week in Pennsylvania matches three shell casings found at the crime scene in Midtown Manhattan, the New York Police Department commissioner said Wednesday, as authorities continue to investigate the motive for the killing.

Also, Mangione’s fingerprints match those investigators found on items near the scene of the December 4 assassination of the UnitedHealthcare chief, Commissioner Jessica Tisch said at a public event.

Three 9 mm shell casings from the crime scene had the words “delay,” “deny” and “depose” written across them, one word per bullet, NYPD’s Chief Detective Joseph Kenny has said. Police have been looking into whether the words, which title a 2010 book critiquing the insurance industry, may point to a motive in CEO Brian Thompson’s killing.

“First, we got the gun in question back from Pennsylvania. It’s now at the NYPD crime lab,” Tisch, the commissioner, said Wednesday. “We were able to match that gun to the three shell casings that we found in Midtown at the scene of the homicide.”

“We’re also at the crime lab able to match the person of interest’s fingerprints with fingerprints that we found on both the water bottle and the KIND bar near the scene of the homicide in midtown,” she said. Authorities had been probing DNA material and a partial fingerprint from a discarded Starbucks water bottle and an energy bar wrapper surveillance images showed the suspect buying about 30 minutes before the shooting.

The fingerprints were the first positive forensic match tying Mangione directly to the scene where Thompson was gunned down just over a week ago outside a hotel, two law enforcement officials briefed on the matter told CNN earlier Wednesday.

Thomas Dickey, Mangione’s Pennsylvania-based attorney, told “Erin Burnett OutFront” Wednesday evening he still needs to see fingerprint and ballistics evidence that New York police say they have.

“Those two sciences, in and of themselves, have come under some criticism in the past, relative to their credibility, their truthfulness, their accuracy, however you want to do it,” Dickey said. “So that’s why as lawyers, we need to see it. We need to see: How did they collect it? How much of it matches? And then we would have our experts … take a look at that, and then we would challenge its admissibility and challenge the accuracy of those results.”

The killing of Thompson – a husband and father of two – has laid bare many Americans’ fury toward the health care industry, with Mangione garnering sympathy online and offers to pay his legal bills. It’s also struck fear in C-suites across the country, as an NYPD intelligence report obtained by CNN warns online rhetoric could “signal an elevated threat facing executives in the near-term …”

The fingerprint and firearms disclosures come as authorities dig into Mangione, who remains in custody in Pennsylvania on gun-related charges as he fights extradition to New York, where he’s charged with murder.

Since his arrest Monday thanks to a tipster at a McDonald’s, the 26-year-old’s background also is starting to come into focus. The privileged scion of a well-to-do family, high school valedictorian and Ivy League graduate vanished from view of his loved ones in recent months, only to emerge as the suspect in a high-profile killing potentially fueled by his struggle with a painful back injury.

Mangione’s mother on November 18 called San Francisco police and reported him missing, saying she hadn’t spoken to him since July 1, a law enforcement official briefed on the investigation told CNN. His mother told authorities she had called her son’s phone repeatedly and the voicemail was full and not taking any more messages, according to the official.

The mother said her son had been living in San Francisco and working remotely for TrueCar, a vehicle buying website, the official said, citing the missing person’s report.