Former NYPD Chief of Department Rodney Harrison weighed in Tuesday on the next steps in the UnitedHealthcare CEO Brian Thompson murder investigation, one day after a suspect was arrested and charged in the case.

Luigi Nicholas Mangione, 26, was arrested Monday in Pennsylvania after a McDonald’s customer alerted authorities to a suspicious man. Police said they found Mangione in possession of a gun, a mask and writings allegedly linking him to the killing.

Manhattan prosecutors charged him with murder and other offenses later that evening, according to court records.

“I think the chief of the detectives put it pretty well when he said this was old-fashioned police work done correctly and leading to an arrest situation,” Harrison said during an interview on “Mornings On 1.” “But there’s still a lot more work that needs to be done.”

Harrison said that the direction of the investigation could hinge on whether Mangione cooperates.

“If he’s willing to talk and tell about what he did and why he did it, then we could go a certain direction in the investigation,” Harrison said. “If he chooses not to talk and requests for a lawyer, then a lot more work needs to be done regarding collecting evidence and matching it up to him and hopefully getting it prepared for a judicial process.”

Harrison also noted that Mangione had an active online presence, which could aid in crafting a narrative.

“The one thing that’s going to be extremely important is putting a story together for the jurors, if it happens to go to trial, collecting every little bit of evidence from beginning to end,” he said.

The former NYPD chief said the next steps in the legal process include potential extradition.

“He’ll be brought in front of a judge, and they’ll look to see if he’s willing to waive extradition,” Harrison said. If not, Manhattan investigators will present their case to a Pennsylvania judge.