NEW YORK — The man accused of shooting dead healthcare insurance CEO Brian Thompson in New York jostled with police and shouted at reporters as he was bundled into court on Tuesday, as more details emerged about a potential motive in the killing.

Luigi Mangione appeared at an extradition hearing in Pennsylvania. His lawyer said the 26-year-old would contest being moved to New York to face murder charges.

"He's pleading not guilty to those offenses," the lawyer said. "I haven't seen any evidence that he's the shooter."

Different US states have different laws and judicial systems, so there is a process involved in the transfer of fugitives, which can take days or weeks.

Wearing an orange jumpsuit, Mr Mangione tried to address reporters as he arrived for the hearing. He was heard shouting "completely unjust" and "insult to the intelligence of the American people" before being taken into court by officers.

Mr Mangione was arrested on Monday after being spotted at a Pennsylvania branch of McDonald's, following a days-long manhunt that spanned several states. He was allegedly found with a gun similar to the murder weapon, a silencer and a fake ID.

Three handwritten pages were allegedly also in his possession. New York police said they took these to be a claim of responsibility in Mr Thompson's fatal shooting, since they appeared to record frustrations with the US healthcare system.

The UnitedHealthcare chief executive, 50, was gunned down by a masked man outside a Manhattan hotel in what authorities have called a targeted attack. — BBC