A man was stabbed by an unknown assailant who escaped Saturday night in Wahiawa, police said.

According to a police report, the victim and a friend were drinking beer in a shack at about 11 p.m. when they heard a noise outside. The man went outside to investigate and was attacked and stabbed in the arm.

He ran inside the shack. The assailant followed and stabbed him again, then fled.

The man flagged down a police car, was taken to a hospital, treated and released.