Graham Dwyer has been convicted of the murder of childcare worker Elaine O'Hara.
The architect stared ahead as the verdict was read out while members of the O'Hara family embraced.
Mr Justice Tony Hunt told the jury he agreed one hundred and ten percent with the verdict finding Graham Dwyer guilty of murder.
It took just over 7 and a half hours of deliberations to reach this point.
The court room fell into hushed silence as the jury returned.
Graham dwyer gave no visible reaction, members of Elaine O'Hara's family embraced.
The evidence was that the pair were in an on and off BDSM relationship and that he stabbed her to death at Killakee to fulfil a deep seated sexual desire.
They will give victim impact evidence on April 20th when Graham Dwyer will formally be sentenced for murder.
