Micheal Martin made the apology in the Dail this afternoon.
The Taoiseach says the family of a Midlands prison officer who was murdered by the IRA was "badly failed" by the State.
Chief Officer at Portlaoise Prison Brian Stack died a year after he was shot in the neck in 1983 after attending a boxing event.
In a formal apology to the Stack family on behalf of the State, Micheal Martin said there were multiple failures in the investigation into his death.
He referenced the mishandling of evidence, the failure to map out the crime scene, and the failure to carry out interviews with his family and friends.
Gardaí also failed to identify the murder's link to the provisional IRA until the Stack family uncovered the truth.
The Taoiseach says Brian Stack is owed a debt of gratitude from the State:
Sinn Fein is apologising for the Republican actions that led to the death of a Midlands prison Officer.
Sinn Fein deputy leader in the Dail Pearse Doherty says Republicans can't hide from the reality of what happened over 40 years ago:
Laois Fine Gael TD Willie Aird says Brian Stack's death was a huge loss to the county:
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