Gardaí are awaiting further tests on the heroin linked to two deaths in Cork city to establish its toxicity.
While initial tests have confirmed that the heroin is not of super-strength, it is thought that it may be higher than what is usually sold in Cork.
Further tests will establish the comparative strength of the batch.
However, the batch had been cut with normal agents such as paracetemol and caffeine.
Gary O’Sullivan, 30, a father-of-one from Douglas, died on Thursday after emergency services were called to an apartment on Blackrock Road.
The second victim, Gavin Thompson, 26, was found dead on Friday in a house in Lansdown Court off the Old Youghal Road.
And on Friday evening, a man was found unconscious on Oliver Plunkett Street after taking the drug.
Emergency crews were able to administer the antidote naloxone, which saved the man’s life.