A Dublin man will be sentenced today for killing his stepson in May 2013.

David Mahon stabbed Dean Fitzpatrick outside his apartment at Burnell Square, Northern Cross on the Malahide road.

David Mahon is married to Audrey Fitzpatrick – the mother of the man he killed during an argument over a water bottle he had stolen from his bike.

At his sentence hearing earlier this month, Audrey’s Victim Impact Statement said she has already forgiven her husband but that it would not be forgotten.

The 45-year-old admitted holding the knife that killed him but claimed it was accident, and even suggested he had wanted to walk onto the blade.

Dean’s death is not the first tragedy to befall the family. His sister Amy has not been seen since she went missing in Spain in 2008.

They had moved over there with Mr Mahon and Audrey four years beforehand.

He was cleared of murder last month but convicted of manslaughter and has been in custody ever since.

He will find out later today what sentence he will have to serve.