The woman in her 20's who was arrested following the sudden and unexplained death of a four-month-old baby has been released without charge.
A file is now being prepared for the DPP.
An investigation is ongoing into the sudden and unexplained death of a four-month-old baby boy in Mayo.
The death occurred following an incident at a residence in Bohola, Co Mayo on December 28.
The baby was taken by ambulance to Mayo University Hospital, Castlebar and later removed to Our Lady's Children's Hospital, Crumlin, where he was pronounced dead on January 1.
A post-mortem examination has been carried out by the State Pathologist and a preliminary report has been forwarded to investigating Gardaí.
It is reported the baby suffered a fractured skull.
A woman in her 20s was arrested yesterday as part of the investigation.
She is currently detained at Claremorris Garda Station under Section 4 of the Criminal Justice Act 1984.
Gardaí have said the investigation is still ongoing.