At least 4 overdose deaths since Thursday linked to possible fentanyl contamination: Toronto police

Toronto police say there have been four overdose-related deaths and 20 overdoses in the city since Thursday and are continuing their warning about a possible round of contaminated street drugs.

Police are warning fentanyl may be mixed with street drugs

Police are warning of a possible contamination of street drugs after a rising number of overdoses in downtown Toronto. (CBC)

Toronto police say there have been four overdose-related deaths and 20 overdoses in the city since Thursday and are continuing their warning about a possible round of contaminated street drugs.

Police suspect that some batches of heroin are laced with fentanyl, according to a news release.

Harm reduction worker Walter Cavalieri said that's become an increasing risk.

"I'm not surprised, he said. "I'm very sad about it, and disappointed.

"I'm really disappointed that we as a city are not taking more actions. This is may be the new normal."

Police say the latest death happened Saturday afternoon when a woman was found in a stairwell in Regent Park, near Queen Street East and Trefann Street. 

She was pronounced at the scene with the initial investigation suggesting her death was drug-related. 

While police say it's too early to determine if her death was fentanyl-related, they have noted similarities with other cases.

Investigators are asking anyone with information to come forward.