A woman in her 40s has died after a violent attack at her home in Co Offaly.

The woman was attacked with a weapon and sustained severe injuries at the house in the Rahan area, around 10km outside Tullamore.

A 16-year-old boy, who was known to the woman, was arrested after gardaí were called to the scene at 1pm.

A murder investigation is under way and the boy is being detained at a local garda station.

He can be questioned for up to 24 hours. Gardaí are not looking for anyone else at present.

The attack was filmed and posted on social media.

Gardaí have warned people to be aware that images of the attack have been circulated on social media.

A local school has issued a warning to parents to be aware of graphic material online.

The scene has been preserved for a forensic examination. The Garda Technical Bureau and the State Pathologist Office have been called in.

The coroner has also been informed.

A senior investigating officer has been appointed and an incident room has been set up at Tullamore Garda Station.

A garda family liaison officer has been appointed to help the family and relatives of the deceased.

In a statement to RTÉ News, gardaí said they were working with Coimisiún Na Mean to get the footage removed from social media.