A Thornlie family were lucky to escape injury when shots were fired at their home early this morning.
Armadale Det-Sen. Sgt Ray Horne said police had not yet identified a motive for the shooting but did not believe the incident was random.
He said at least five shots were fired at the Camborne Way house at 2.30am.
"Two of the rounds have gone through the front door and three rounds have hit the front wall of the house," Det-Sen. Sgt Horne said.
"Two projectiles have been located - one just inside the front door and one about 3m inside in a (hallway) wall.
"It ended up in a book and it was some distance away from where the people were sleeping."
He said a 43-year-old woman, 35-year-old man and two children - aged 16 and five - were asleep in the home at the time but fortunately none were injured.
"We're hoping we can find witnesses or someone with information," he said.
Det-Sen. Sgt Horne said police suspected the shots were fired from a car and one witness had told police they heard a car leaving the area around the time of the incident.
Early indications were that a handgun had been used.
Den-Sen. Sgt Horne said the residents were obviously shaken and concerned and had not told police they had been the victims of any previous threats.
"WA Police treat these incidents very seriously, it was very lucky today that none of the occupants were hurt but it could have been worse," he said.
A neighbour who lives just two doors away said he had just arrived home from his night shift job when he heard three loud bangs followed by a noise that sounded like an explosion.
He went outside but did not see anything. He said he heard one more bang but didn't realise at the time it was a gunshot.
He said it was frightening to think that shots had been fired in his street.
Ballistics and forensic officers were scouring the scene this morning to try find projectiles and shell casings, while detectives are searching for witnesses and other evidence.
Anyone with information is asked to call Crime Stoppers on 1800 333 000.