The loyalist Ulster Volunteer Force is being blamed in backstreet Belfast for pushing drugs which are suspected of causing eight deaths in the city in recent weeks.
Individuals in the illegal paramilitary group are known to be major dealers in the trade which has made drugs freely available in inner-city areas, especially those in which the loyalists are active.
Calls for police to take more action are being led by Northern Ireland First Minister Peter Robinson, who represents the east Belfast area where much of the problem is centred and where five of the deaths have taken place.
He declared: "The police cannot relax on these matters. They need to pursue, because it is well-known who is selling drugs in east Belfast. I think the police have to act."
Police have reacted angrily to allegations that some paramilitary figures have not been pursued, insisting there are "no untouchables" in the drugs world.
Formal forensic tests have yet to confirm that the deaths were drugs-related, with both police and health authorities saying they are awaiting the results of tests.
But police and chief medical officer Dr Michael McBride have warned that particularly strong and potentially lethal drugs, including one known as Green Rolex, are in circulation.
A relative of one of those who died, 33-year-old father-of-four Jim Owens, said her family believed he may have taken an ecstasy tablet contaminated with other drugs. He was found unconscious in the Shankill Road district on Sunday.
His sister Diane Potter declared: "I would appeal for young people not to take anything at all. I'm appealing from the bottom of my heart - please let this be a wake-up call. It's not worth risking your life."
Police Detective Superintendent Philip Marshall said several different types are suspected to be involved, adding: "There's some indication and some discussion around the potential use of drugs in some of those cases. We've information that a drug known as a green Rolex may be involved, but that is not in all incidents."
Dr McBride said one possibility was the existence of a stimulant drug similar to ecstasy, but which did not act as quickly. He said: "Users may believe they have taken a 'weak' ecstasy tablet, when they have actually taken a tablet containing this highly toxic substance.
"They may then be tempted to take more tablets to achieve the desired effect, increasing the risk of a potentially fatal overdose."
While much of the UVF has been relatively inactive, its east Belfast section has in recent years been to the fore both in drug-pushing and in occasional outbursts of rioting. Figures associated with the organisation in other areas admit that the east Belfast unit regards itself as largely independent.
Pastor Paul Burns, who knew one of the victims, called on police to act, saying: "These people are selling death and lining their pockets. I would call on community leaders to get this stuff off the street. We don't want to see any more young people dying."