Cannington Detectives are investigating an assault incident around 11:30am on Saturday 29th December 2018, where a truck driver stopped along Pinedale Street to assist an elderly man being threatened by three juvenile males carrying bricks.
He took one of the bricks from the boys and ordered them to leave, before re-entering his truck and driving away.
One of the boys ran back to the truck and threw a brick into the open cab window, striking the victim in the head and damaging the front windscreen.
The boys ran away along Pinedale Street before turning right onto Creaton Street.
The man received serious head injuries as a result of the incident and was treated at Royal Perth Hospital.
Police have released CCTV vision of three boys they wish to identify and believe they may be able to assist them with inquiries.
Anyone with information regarding this incident is asked to contact Crime Stoppers on 1800 333 000 or make a report online at crimestopperswa.com.au.