Police are investigating a report that a shot was fired at a stationary car in Perth’s northern suburbs while a couple were sitting inside it.

About 8:35pm yesterday a 42-year-old man and his 38-year-old female partner were sitting in their vehicle in an alleyway off Whitehouse Drive in Koondoola eating takeaway food.

A man banged on the driver’s window with what they believe was a firearm and spoke to the couple.

Police said it was then reported that he fired the weapon into the rear door of the vehicle on the driver’s side.

The victims drove away and contacted police.

The offender was described as being fair-skinned, around 175-180cm tall and of a medium-thin build.

He also had a goatee beard and was wearing a blue hoodie and jeans.

A Ford Falcon was seized by police for forensic examination.

Anyone with information is asked to call Crime Stoppers on 1800 333 000.