But Reddy's lawyer, Jonathan Krebs, said the killer was not his client but a man called James whom Ms Yusef was seeing romantically.
Mr Krebs asked why he told undercover police he had committed the murders if he had not.
"Earlier on when I told them James had done this they did not believe James had done this," he said.
"I took it all on myself because James wasn't [known to the undercover police]."
Mr Krebs asked him how he was able to take police to the burial site and show them where the bodies were buried if he was not involved in burying them.
There is a photo of Reddy standing on the site where the bodies were buried.
"[The undercover officer] told me to go under the bridge, I didn't know that he was taking a photo."
The Crown said the defendant and adult victim had been in a relationship at the time.
Reddy today denied being in a relationship with Ms Yusef or ever living or staying at her home in Howick.
Crown Prosecutor Natalie Walker asked Reddy why he did not mention James to any family, police or acquaintances.
"You never named James did you, and you could have?"
Reddy said that he did tell an undercover officer about him.
Mr Reddy said to Ms Walker he did not remember pleading guilty to a charge of threatening to kill Ms Yusef in 2006.
He did remember completing anger management classes, but could not remember why.
"When you were charged with threatening to kill Pakeeza there was a condition of your bail that you were not to associate with her, do you remember that?
"Initially the two of you just ignored that court order while you were continuing to have relationship but after a while Pakeeza didn't want to have you around anymore."
Mr Reddy said: "It's not true."
He also denied physically and verbally abusing her in violent episodes that she would tell her mother in Fiji about.
"When you treated her like this she would understandably get upset and call her mother on Fiji."
He said: "I have never sworn at my own children so why would I swear at Pakeeza?"
Ms Walker said the incidents became increasing frequent in December 2006.
Mr Reddy said he made up the stories he told undercover police officers about the way he treated Ms Yusef.
Those conversations were secretly recorded and the transcripts read out in court today.
"I made up a story. I made up these stories to get James' problems fixed."
Ms Walker said Ms Yusef's mother was never told about a man called James.
Details of the undercover police operation have been suppressed and were discussed in closed court today.
The trial continues.
