A 20-year-old man has died in Dublin after being found with serious injuries on Halloween night.

A murder investigation has been launched.

The victim was found on the Old Blessington Road in Tallaght at around 3am on November 1.

He was taken to Tallaght Hospital and then to Beaumont with a serious head injury, but lost his fight for life earlier today.

A post mortem was carried out and following this, the investigation has now been upgraded to murder.

It is believed he had been assaulted.

A 20-year-old man was arrested in Tallaght earlier today as part of the investigation, and is being held at Tallaght Garda Station where he can be questioned for up to 24 hours.