Las Vegas police say they're interviewing another possible suspect in the robbery investigation involving O.J. Simpson.

Police Lieutenant Clint Nichols says the man is believed to be an associate of Simpson's who was voluntarily undergoing questioning Saturday.

No arrests have been made.

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Police believe the man was part of a group that accompanied Simpson into a hotel room at the Palace Station casino on Thursday night.

Two sports memorabilia collectors are accusing Simpson and the men of busting into the room and stealing collectibles at gunpoint.

Simpson denies weapons were involved. He says the items rightfully belong to him.