A man remains in custody in the investigation into the murder of Ashling Murphy.
The man, who is aged in his 30s, was arrested on Tuesday in Co Offaly, on suspicion of murder.
Irish police said the man is being questioned at Tullamore Garda station.
The arrest was made after police renewed an appeal for information, saying “significant progress” had been made with their investigation
The body of Ms Murphy, a talented musician and teacher, was found on the banks of the Grand Canal in Tullamore last Wednesday.
Large crowds gathered in the village of Mountbolus and outside St Brigid’s Church, where her funeral was held on Tuesday.
Mourners included Irish president Michael D Higgins and Irish premier Micheal Martin.
Vigils have been held across Ireland and the world to remember Ms Murphy and to call for a change in tackling gender-based violence.