A man in his 30s has been arrested by Gardaí (Irish police) investigating the murder of Ashling Murphy.
The 23-year-old primary school teacher was attacked while out exercising beside a canal in Tullamore, County Offaly, last Wednesday.
The man is being questioned in relation to potential withholding of information.
Another man in his 30s, who was arrested on Tuesday, continues to be questioned on suspicion of murder.
A 40-year-old man was arrested last week, but was later released and eliminated from police enquiries.
Tens of thousands of people have attended vigils across the island of Ireland and further afield following Ms Murphy’s killing.
Mourners turned out on Tuesday for her funeral with Irish President Michael D Higgins and Taoiseach (PM) Micheál Martin among those who attended.
In the wake of Ms Murphy’s murder, there have been calls for more to be done to tackle violence against women in Ireland.