The notebook of Luigi Mangione, a murder suspect, was labeled "wack" by the CEO of the targeted company.

• A notebook discovered with Luigi Mangione has a description of the murder of UnitedHealthcare CEO Brian Thompson in New York last week, which matches the details of the alleged killing.
• An Ivy League graduate was arrested in Altoona, Pennsylvania, and a gun, silencer, and ammunition were found in a backpack he had with him at a McDonald's.
• Fingerprints found near the Hilton hotel in midtown Manhattan match some of those taken from Mangione, who was fatally shot while heading to an investor meeting for UnitedHealth Group.

Luigi Mangione's notebook contained a description of killing a CEO that matches the details of the alleged murder of UnitedHealthcare's CEO in New York last week, according to NBC News.

"What do you do?" a section of the notebook says.

"The notebook records that you targeted and precisely hit the CEO at the annual parasitic bean-counter convention, without putting innocent people at risk."

An Ivy League graduate was arrested in Altoona, Pennsylvania, on Monday and a gun, silencer, and ammunition were found in a backpack he had with him at a local McDonald's.

On Wednesday, NBC reported that fingerprints found near the Hilton hotel in midtown Manhattan match some of those taken from Mangione, the UnitedHealthcare CEO who was fatally shot on Dec. 4.

At the Hilton, an investor day hosted by , a father of two, Thompson, was scheduled to speak that morning.

A masked man with a silenced gun shot Thompson from behind, just outside the Hilton, as another person watched.

After Thompson's murder, NYC Police Commissioner Jessica Tisch stated that all signs point to a premeditated, preplanned, targeted attack.

According to previous reports, Mangione was found with a handwritten note that read, "These parasites simply had it coming," when he was arrested in Altoona.

The note, which stated that he was not collaborating with anyone, also included an apology for any distress caused, but it was necessary.

The note criticized UnitedHealthcare, the U.S. health-care industry and corporations.

For years, Mangione, who holds two degrees from the University of Pennsylvania, has reportedly suffered from significant back pain.

In the U.S., the largest private health insurance payer, UnitedHealthcare, has faced criticism for rejecting customers' health insurance claims.

Mangione is being held in Pennsylvania without bail on state firearms and forgery charges related to his arrest. The forgery charge pertains to his alleged possession of multiple false identification documents, including one that was reportedly used to check into a hostel on Manhattan's Upper West Side nearly two weeks before Thompson's murder.

He is charged with murder and gun crimes in Manhattan.

In a Blair County Court hearing on Tuesday, Mangione declined to relinquish extradition to New York to answer charges there for Thompson's murder.

The Manhattan District Attorney's Office and New York Gov. Kathy Hochul announced that they will submit the necessary documents to a Pennsylvania judge to determine whether to extradite Mangione.

— WNBC's Jonathan Dienst contributed reporting.