A woman arrested over the sudden and unexplained death of a four-month-old baby has been released without charge, gardai said.
The baby boy died on New Year's Day following what investigators described as "an incident" at a house in Bohola, Co Mayo, on December 28.
He was first taken by ambulance to Mayo University Hospital in Castlebar and was later moved to Our Lady's Children's Hospital in Crumlin, Dublin, where he was pronounced dead.
A post-mortem examination has been carried out by the State Pathologist.
Gardai said they would not release details of a preliminary report for "operational reasons".
A woman in her 20s was arrested on Wednesday as part of the investigation.
She was questioned at Claremorris Garda Station under Section 4 of the Criminal Justice Act 1984.
The woman was released from custody without charge on Thursday morning and a file is being prepared for the Director of Public Prosecutions.
A Garda spokesman said: "The investigation is ongoing."