Homicide detectives are knocking on doors in Perth’s northern suburbs in a bid to solve a decades-old murder.

Andrew Podpinka’s wife and daughter returned from shopping in March 1999 to find him stabbed to death at the family home in Morley.

WA Police Detective Acting Inspector Lloyd Van Der Schoor told Larry Graham the 43-year-old was last seen collecting his mail before he was found in the master bedroom with extensive wounds to his chest and back.

The WA government has offered a $250,000 reward for information leading to a conviction, and people who come forward may be granted immunity from prosecution.

Tap PLAY to hear more about the cold case investigation below.