Police arrested a suspect in the robbery of an unattended laptop computer at a Kapiolani Boulevard business late last night.

The victim, 26, left his laptop unguarded as he went to speak to a friend about 50 feet away, police said. The victim watched as a man picked up and carried his laptop away.

When the victim demanded his laptop back, the robber pushed him and punched him in the arm before fleeing, police said.

The victim and several bystanders caught the suspect at a nearby business on Keeaumoku Street and detained him until police arrived. The 25-year-old suspect, of no permanent address, is being held pending a second-degree assault charge, according to police.