London police are warning drug users following three suspected overdose deaths and two hospitalizations in the past three days.

Police say dangerous opioids like fentanyl can be mixed in with other drugs such as cocaine and ecstasy.

On Monday afternoon, police were called to an address on Maitland Street where a 39-year-old woman was found dead and a man in critical medical distress.

Just before 11 a.m. Wednesday, investigators returned to the same address and found another man dead and another in serious distress.

Also this past Monday, police attended an address on Wonderland Road after a woman as found dead of a suspected overdose.

“At this point, we are waiting on toxicology results but we feel it is important to warn people immediately,” Steve Williams, Deputy Chief Operations, said in a news release. “We don’t know if it is related to illicit opioid use or another drug, but once again, we are urging people to be careful if they are going to use any drug because we know fentanyl and carfentanil are in London.”

Since the beginning of the year, London Police have responded to a total of five suspected fatal overdoses.