Human remains discovered during building works at the rear of a house in Dundalk yesterday are historical and not of modern or recent origin.
Gardaí say while the gender or age of the deceased has not yet been determined, the remains are not those of missing Dundalk woman Ciara Breen.
The 17-year-old left the home she shared with her mother Bernadette on the night of 13 February 1997 and never returned.
Gardaí also said that the remains are not connected to any ongoing garda investigation.
Last night a forensic anthropologist confirmed that the remains, which were discovered in the back garden by a builder renovating the house on Mary Street North, were human.
The houses on the street are very old - with one local saying they were built over 100 years ago.
They are mainly terraced and a mix of one and two-storey.
State Pathologist Dr Marie Cassidy and a forensic anthropologist visited the scene this morning.
Gardaí have said that the process ahead will be "slow" and there will be careful excavation to ensure all of the remains are recovered.
Superintendent Gerry Curley said gardaí will be in contact with the National Museum of Ireland to decide which way to proceed.
