Luigi Mangione seemed "nervous" and claimed he was homeless when a Pennsylvania police officer confronted him inside a McDonald's restaurant last December, the law enforcement officer testified during a pretrial hearing Tuesday.

The tense encounter ultimately led to Mangione's arrest, capping off a five-day national manhunt. Mangione, 27, pleaded not guilty to state and federal charges in the fatal shooting of UnitedHealthcare CEO Brian Thompson outside a Manhattan hotel.

Altoona Police Officer Joseph Detwiler took the witness stand Tuesday in Manhattan Criminal Court as part of a complex hearing focused on Mangione's lawyers' bid to exclude evidence from his state murder trial. The proceedings could last at least a week.

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