A 28-year-old woman who left her engine running while visiting family in Waikiki found a man sitting in her driver’s seat who then allegedly hit another woman over the head with a beer bottle when she tried to intervene, police said.

The 53-year-old woman who was struck on the head was taken to the Queen’s Medical Center in serious condition following the 11:15 p.m. attack, police said.

The 57-year-old suspect had been drinking beer in his carport when the driver pulled up in front of the carport and left her vehicle running and the doors unlocked, police said.

The driver later saw the man inside her driver’s seat, took the keys and ordered him to leave, police said. 

He then allegedly hit the 53-year-old woman with the beer bottle when she confronted him, police said. 

The man was arrested on suspicion of assault in the second degree and unauthorized entry into a motor vehicle in the second degree.