The incident happened shortly after 11am on Friday, 12 September in the Connaught Gardens in Athlone, next to the Corpus Christi Catholic church.
A woman in her 30s was taken to Midland Regional Hospital in Tullamore for treatment of serious injuries.
A man in his 60s was arrested at the scene and detained at a Garda station in Westmeath.
He has since been released without charge and a file will be prepared for the Office of the Director of Public Prosecutions.
Gardaí are appealing for any witnesses to come forward.
Anyone who was in the area of Connaught Gardens by the Corpus Christi church on Friday, 12 September between 10:45am and 11:30am is asked to make contact with gardaí.
Anyone with information is asked to contact Athlone Garda Station on 090 6492600, the Garda Confidential Line 1800 666 111, or any Garda station.
Investigations are ongoing.