All four people found dead in a suburban Melbourne home, including a 17-year-old, had synthetic opioids in their system.
Police were called to a Broadmeadows house in Bicknell Court just before 2am on June 26, after a neighbour went to check on the house and discovered the bodies.
Michael Hodgkinson, 32, was one of four people discovered in the loungeroom of a unit along with Abdul El Sayed, 17 and an as-yet unidentified 37-year-old man and a 42-year-old woman.
Victoria Police on Thursday said their investigation into the Broadmeadows deaths is ongoing, but confirmed the drug find.
'Preliminary tests have confirmed the presence of a synthetic opioid in the system of all four people,' the force said in a statement.
'No presence of fentanyl has been detected at this time.
The Department of Health on Tuesday released a warning about cocaine in Melbourne being sold laced with synthetic opioid protonitazene, which is 100 times more potent than heroin.
'There have been recent serious harms in Melbourne associated with a white powder sold as cocaine that contained protonitazene,' the warning stated.
Michael Hodgkinson was among four killed in a suspected overdose at Broadmeadows last week
Abdul El Sayed, 17, (right) leaves behind a partner and an 18-month-old daughter
'The product appears to produce such as loss of consciousness, respiratory depression, and life-threatening hypoxia (insufficient oxygen for normal functioning).'
The bodies were found by a relative and were all in the same area of the house, leading police to believe they were sitting together and there was no evidence to suggest there had been any violence inside the home.
Preliminary forensic testing has confirmed all four people had a synthetic opioid in their system (pictured, family and police at the home where the four bodies were discovered)
Police are probing the "unusual" death of four people found at a home in Melbourne's north. (William Ton)