Graham Dwyer's murder trial has been hearing evidence from a man who says he met childcare worker Elaine O'Hara on a sex web site.
The architect from Kerrymount Close, Foxrock denies stabbing the 36-year-old for his own sexual gratification in the Dublin mountains in August 2012.
Robert Cullen Jones said he met Elaine O'Hara in March 2011 on alt.com a website for people who like to be submissive or dominant in sexual relations.
His profile name was Dublin_master while the childcare worker used 'helpmelearn36f'.
He said they met in Dundrum Shopping Centre in April 2011 and went to her apartment for sex.
The jury heard she showed him sexual paraphernalia like handcuffs and vibrators, discussed her fantasies about bondage and said she was involved with another man who she didn't name.
He said they met in Dundrum again May 2012 - she mentioned being depressed and they didn't go back to hers. He said it just sort of fizzled out after that.