A man in his 40s has died after he was stabbed in Tallaght in Dublin.
It happened following a row in a house at Castle Park.
A man was arrested at the scene and taken to Tallaght Garda Station.
It is understood that he knew the victim.
Emergency services were called to the house just before 9pm last night.
They discovered an injured man inside.
Paramedics treated the victim at the scene but he was pronounced dead a short time later.
His body remains at the scene.
A number of other people were in the house at the time.
The scene has been sealed off as a crime scene and the State Pathologist's Office has been informed.
Specialists from the Garda Technical Bureau and Forensic Science Ireland are set to carry out an examination of the house.
The teenager is being detained under Section 4 of the Criminal Justice Act and can be questioned for up to 24 hours.
Gardaí have begun a criminal investigation and believe the weapon used in the stabbing remains at the scene.
An incident room has been set up and a senior investigating officer and a family liaison officer are to be appointed.
Detectives are following a definite line of inquiry and are not looking for anyone else at present.
