Forensic investigators have been called in after a man tending his suburban garden uncovered a human skull.
The homeowner had been digging in the back garden of his house in the Killakee estate in Firhouse, south Dublin, when he came across the remains.
The state pathologist as well a forensic anthropologist are helping the Garda with their investigation.
Preliminary tests suggest the skull was that of an adult aged between 18 and 40 years old.
A Garda spokesman said it may have been in the ground from as far back as the mid-1940s.
DNA tests and other forensic analysis will be carried out on the remains in an attempt to positively identify the skull.
A review is also being launched of unresolved missing person files to see if there are any clues.
However, the Garda spokesman said no link to any missing person has been made at this early stage of the investigation.
“The scene has been preserved for technical examination,” he added.
“Investigations are ongoing.”