Gardai said the man, in his 30s, was being held at a police station in the east of the country.

He is being questioned over the potential withholding of information.

It follows the arrest on Tuesday of another man, also in his 30s, on suspicion of Ms Murphy's murder.

He is being held at Tullamore Garda Station in central Ireland.

Officers previously said they were making "significant progress" in their investigation.

Ms Murphy, 23, was found dead after going for a run on the banks of the Grand Canal in Tullamore, County Offaly, at around 4pm on 12 January.

A funeral was held for her on Tuesday, during which she was remembered as a "woman who made a difference, who brought happiness and who was loved".

Father Michael Meade, who addressed the mass, said Ms Murphy's parents, siblings and boyfriend had been "robbed of your most precious gift - a gift that gave only joy and love, fun and laughter to many beyond your family".

Mourners included Irish president Michael D Higgins and Irish premier Micheal Martin.

There have been calls for a change of approach in tackling gender-based violence and vigils have been held across Ireland.