Five people who were in Garda custody following a seizure of heroin in Galway on Thursday have been released without charge and a file is to be prepared for the Director of Public Prosecutions.
Two more men have been arrested in relation to the investigation.
They are in custody at Galway Garda station under Section 4 of the Criminal Justice Act.
Heroin worth €4,000 was recovered in a search of a house on Dominic's Road in the city.
During the garda operation a pit bull terrier attacked a garda, who received extensive leg injuries.