UnitedHealthcare CEO killing latest: Luigi Mangione allegedly wrote about plan to ‘whack’ CEO, sources say

(NEW YORK) — Fingerprints taken from Luigi Mangione, the suspect in the killing of UnitedHealthcare CEO Brian Thompson, appear to match fingerprints recovered from items found near the shooting scene, law enforcement sources told ABC News.

The prints recovered from a water bottle and a cellphone were smudged, but the sources said they appear to match the prints sent from Altoona, Pennsylvania, where Mangione was arrested on Monday.

If confirmed by detectives, it would represent the first forensic tie between the murder and 26-year-old Mangione.

Mangione also allegedly had a spiral notebook detailing plans about how to eventually kill the CEO, according to law enforcement officials.

One passage allegedly said, “What do you do? You whack the CEO at the annual parasitic bean-counter convention,” the officials said.

The writings said using explosives in the attack could “risk innocents,” according to the officials.

Detectives are still examining Mangione’s writings but are considering the contents of the notebook to represent a confession, sources said.

Investigators have started interviewing members of Mangione’s family, according to sources.

Mangione plans to challenge his extradition from Pennsylvania to New York, where he faces a charge of second-degree murder in connection with Thompson’s Dec. 4 shooting death outside a Midtown Manhattan hotel.

“He has constitutional rights and that’s what he’s doing” in challenging the interstate transfer, defense attorney Thomas Dickey told reporters on Tuesday.

Mangione is “taking it as well as he can,” Dickey added.

The Manhattan District Attorney’s Office said it will seek a governor’s warrant to try to force Mangione’s extradition. New York Gov. Kathy Hochul said in a statement that she’ll sign a request for the governor’s warrant “to ensure this individual is tried and held accountable.”

A judge in Pennsylvania ordered Mangione held without bail on Tuesday.

The Ivy League graduate was arrested on Monday in Altoona and charged in Pennsylvania for allegedly possessing an untraceable ghost gun.

New York police have not said whether the gun recovered in Pennsylvania is considered a match for the one used in the Midtown killing, but said it looks similar and that it would undergo ballistic testing.

Mangione’s attorney told ABC News’ “Good Morning America” on Wednesday that he had “not been made aware of any evidence that links the gun that was found on his person to the crime.”

“A lot of guns look the same,” Dickey said. “If you brought a gun in and said, ‘Well, it looks like that,’ I don’t even know if that evidence would be admissible. And if so, I would argue that it wouldn’t be given much weight.”

Dickey also cautioned that anyone speculating on the case should take the potential evidence “in its entirety,” not taking pieces of writing or other evidence “out of context.”

“People put out certain things, parts of different things,” he said. “I think any lawyer involved in this situation would want to see it all.”

Mangione plans to plead not guilty to the charges in Pennsylvania, Dickey said. Dickey said he anticipates Mangione would also plead not guilty to the second-degree murder charge in New York.

ABC News’ Sasha Pezenik, Mark Crudele, Luke Barr, Peter Charalambous and Josh Margolin contributed to this report.