The 42 year old architect with an address at Kerrymount Close, Foxrock denies murdering the childcare worker in August 2012.
The prosecution alleges Graham Dwyer was in a sado-masochistic relationship with Elaine O'Hara and that he stabbed her to death to satisfy his sexual desires.
The 36 year old childcare worker was last seen near Shanganagh cemetery in Dublin on the evening of August 22nd 2012.
Her partial remains along with tracksuit bottoms, and a runner were found by a dogwalker in a rough wooded area of the Dublin mountains on September 13th the following year.
Gardaí have this morning given evidence of preserving the scene _ the defence does not deny that the bones found were those of Elaine O'Hara.
The dogwalker Magali Vergnet said she also saw a rusted knife but gardaí who initially attended the scene said they don't recall being made aware of this.