Gardaí are hopeful the results of toxicology reports carried out on the remains of six drug addicts will reveal if they died after taking a bad batch of heroin.
The six, five men and a woman, have all died in Dublin since last weekend following apparent heroin overdoses.
Drug user associates of all six victims, who are aged between 26 and 40, have been interviewed by gardaí over the weekend in an effort to establish whether the victims bought their heroin from the same street dealers or even in the same areas of the city.
Four of the victims, three men and a woman, had inner city addresses and all died in the Mater hospital after collapsing of suspected overdoses. Another victim, from Blackrock, died after being rushed to St Vincent's hospital. The sixth victim died at Beaumont Hospital after collapsing at home in Portmarnock.
Informed Garda sources have told The Irish Timesthat while six suspected heroin deaths in a 10-day period is unusual there was nothing, as yet, to suggest all were linked to same batch of heroin.
"We haven't even established that they are all heroin overdoses," said one source.
"While all the reports over the weekend said they were heroin deaths it now appears that some of them had taken cocaine as well as heroin. But we won't know for sure what role heroin played until we get the toxicology reports."
Those results were expected to be available at Beaumont Hospital as early as today.
Gardaí said the results should establish if the purity of the drug was the same in all cases and if there were other common features.
All of those who died were drug addicts who were known to gardaí. At least three were registered methadone users.
Joe Costello TD (Lab), in whose Dublin Central constituency four of the deaths took place, said the cases highlighted the need for greater resources in tackling heroin addition.
He believed the deaths could be linked to the greater availability of poorer quality heroin from Afghanistan.
