The man charged with killing UnitedHealthcare CEO Brian Thompson was not a client of the medical insurer and may have targeted it because of its size and influence, a senior police official said Thursday.

NYPD Chief of Detectives Joseph Kenny told NBC New York in an interview Thursday that investigators have uncovered evidence that Luigi Mangione had prior knowledge UnitedHealthcare was holding its annual investor conference in New York City.

Mangione also mentioned the company in a note found in his possession when he was detained by police in Pennsylvania.

“We have no indication that he was ever a client of United Healthcare, but he does make mention that it is the fifth largest corporation in America, which would make it the largest healthcare organization in America. So that’s possibly why he targeted that company,” said Kenny.

UnitedHealthcare is in the top 20 largest U.S. companies by market capitalization but is not the fifth largest. It is the largest U.S. health insurer.

Mangione remains jailed without bail in Pennsylvania, where he was arrested Monday after being spotted at a McDonald’s in the city of Altoona, about 230 miles (about 370 kilometers) west of New York City. His lawyer there, Thomas Dickey, has said Mangione intends to plead not guilty. Dickey also said he has yet to see evidence decisively linking his client to the crime.

Mangione’s arrest came five days after the caught-on-camera killing of Thompson outside a Manhattan hotel.

Police say the shooter waited outside the hotel, where the health insurer was holding its investor conference, early on the morning of Dec. 4. He approached Thompson from behind and shot him before fleeing on a bicycle through Central Park.

Mangione is fighting attempts to extradite him back to New York so that he can face a murder charge in Thompson’s killing. A hearing has been scheduled for Dec. 30.

The 26-year-old, who police say was found with a “ ghost gun ” matching shell casings found at the site of the shooting, is charged in Pennsylvania with possession of an unlicensed firearm, forgery and providing false identification to police.

Mangione is an Ivy League graduate from a prominent Maryland real estate family. In posts on social media, Mangione wrote about experiencing severe chronic back pain before undergoing a spinal fusion surgery in 2023. Afterward, he posted that the operation had been a success and that his pain had improved and mobility returned. He urged others to consider the same type of surgery.

On Wednesday, police said investigators are looking at his writings about his health problems and his criticism of corporate America and the U.S. health care system.

Kenny said in the NBC interview that Mangione’s family reported him missing to San Francisco authorities in November.

(AP)