A murder investigation has been launched after a 23-year-old primary school teacher was fatally attacked as she jogged along a canal in Ireland.

Ashling Murphy, who taught at a school in Tullamore, Offaly, was found beside the Grand Canal at Cappincur at around 4pm on Wednesday.

Detectives believe the 23-year-old, who died at the scene, was attacked by one man acting alone.

A 40-year-old man has been arrested in connection with her death and is being held at Tullamore Garda Station.

Superintendent Eamonn Curley said during a press briefing the force’s prayers are with Ms Murphy’s family, the community, her colleagues and “the children who are without their teacher today”.

He added: "Immediately following the discovery of this crime, a full-scale murder investigation was launched. At this stage, there is no information that the victim and her killer were known to each other."

Supt Curley added Garda is keeping an "open mind" as he appealed to the public for assistance and asked any witnesses to come forward.

Declan Harvey, Fianna Fail councillor for the area, said the primary school teacher had been out jogging when she died, adding: “I am devastated.”

“I couldn’t sleep last night thinking of it all because it is a place I go all the time,” he said.

"She went there jogging, she does it regularly. I am lost for words."

Mr Harvey said it is a route that he and his family often walk, adding: “Tullamore is probably the safest place in the world, and after yesterday people will be nervous to go down to the canal.

"It's a lovely area and helps clear your head. It's a very popular route that everyone takes. People walk their dogs, people with their kids and prams."

The Office of the State Pathologist and the Garda Technical Bureau have been notified, and an incident room has been set up at Tullamore Garda Station with more than 50 gardai working on the investigation.

They have asked anyone who was in the area before 4pm on Wednesday to make contact with them.

Josepha Madigan, minister of state for special education and inclusion, said: "A young woman can't even go for a run along a canal pathway – at four o'clock, in the middle of the day – only to be attacked and murdered.

"Sincere sympathies to her family. We need to urgently address why we live in a country where this can happen."