Graham Dwyer has been jailed for life for the murder of childcare worker Elaine O'Hara.
Mr Justice Tony Hunt described the architect as a 'very dangerous man' and said it was a sentence he 'richly deserves'.
In a victim impact report prepared by her father Frank, they said this is their life sentence without parole.
Graham Dwyer was convicted of killing the 36 year old last month.
The jury found he was in a BDSM relationship with Elaine O'Hara and stabbed her to death at Killakee mountain in August 2012 for his own sexual gratification.
Elaine's family describe her as 'a very intelligent girl who never fully realised her potential due to her psychological difficulties'
Their impact report said the trial has been incredibly difficult because her private life was laid bare before the nation despite the fact that she was the victim.
They said it was 'heartbreaking to listen to the texts she received from the 'depraved and diseased mind' of Graham Dwyer
Imposing the mandatory life sentence for murder, Mr Justice Tony Hunt said the architect was in a place of denial, arrogance and delusion
He said the architect was a 'very dangerous man' and that the sentence was one he 'richly deserves'