Father charged

Anthony Robert Harvey, 24, is accused of killing his twin two-year-old girls, his three-year-old daughter, his partner and his mother-in-law.

Their bodies were found at the Coode St home on Sunday after Harvey visited a local police station.

The tragedy has stunned neighbours, who haven't seen the family in over a week.

"We thought they were on holiday, they haven't been there all week," Desrae Cambos told 7 News.

One neighbour told WA Today she often saw children playing in front of the house.

Police have apprehended the suspect and are still investigating the matter.

Police Spokesperson Su’a Le Mamea Tiumalu says injuries on the boy’s neck appear to have been caused by a sharp object.

“The father of the deceased was having a drinking party with some of his friends and later that night he got into an argument with his wife. We believe this led to the wife running off and the accused sent his son to find her,” said Su’a.

He added that the Police findings so far reveal that the boy came back home without his mother which led to the incident.