A 23-year-old man, who became ill at a homeless hostel in the midlands on Monday, has died in hospital.
The man, whose girlfriend also died in the hostel last Monday, is from the Portlaoise area.
He had been a resident in emergency accommodation in Tullamore, Co Offaly.
A garda investigation is under way into the incident.
The man and woman had been residing at the old Clonamore House Hotel in Tullamore.
A 44-year-old woman who was found unresponsive at the hostel on Sunday 26 April was pronounced dead a short time later.
The hotel closed several years ago but ten bedrooms in the building have been outsourced to Laois, Offaly and Westmeath county councils providing hostel accommodation for homeless people in the three counties.
However, there has been criticism of the period of time some residents have been housed there while waiting for alternative accommodation.
Gardaí had issued a warning about the origin of substances or drugs which may have been bought on the internet, and are being circulated in the midlands.
Earlier this week, Chief Superintendent John Scanlon said gardaí are investigating the circumstances surrounding all of the deaths but wanted to issue strong advice to drug users.
"Anybody should be very careful taking substances that they do not know of their origins," he said. "Anybody who may have taken substances that they are unsure of should make immediate contact with a healthcare professional".
Garda Commissioner Drew Harris said it was "very probable that a cocktail of drugs" was involved in the deaths of the three people.
He said gardaí were seeing "the difficulty for gangs street dealing" and people were moving on to counterfeit and prescription drugs and selling them on.
He said the circumstances that took the lives of these people were tragic, but there was always a danger when people engage in drug abuse, and in the circumstances where they may take a cocktail of drugs, that there can be a fatal outcome.
