Simon Gittany was convicted in 2013 of murdering his fiancee Lisa Harnum in 2011.Credit:Ben Rushton
All three judges of the NSW Criminal Court of Appeal dismissed his appeal.
During a hearing in June,Gittany's barrister,Stephen Odgers,SC,questioned the testimony of ABC producer Joshua Rathmell,the Crown's key witness.
Murdered:Lisa Harnum.
At trial,Mr Rathmell said he was walking in Hyde Park when he heard the sound of"deranged screaming".
It prompted him to look up to the top of The Hyde,a luxurious apartment block in Liverpool Street.
Mr Rathmell said he saw someone"unloading"something from the building.
"I saw the man load the object off the balcony,and in what I described as a fluid motion,turned and went straight back into the apartment,"he said."I didn't really follow the item."