A man accused of murdering his County Durham girlfriend and burying her in a shallow grave told her son they had rowed about her injecting herself with Botox before she disappeared, a court heard.
Adrian Muir, 50, from Halifax, West Yorkshire, began a relationship with grandmother Pamela Jackson, 55, after they met on the Fling.com dating site, Newcastle Crown Court heard.
She disappeared from her family home in Chester-le-Street on Saturday March 2. Her body was found 120 miles away on the moors above Halifax on May 27.
Muir, a stonemason and keen guitarist, denies her murder.
Five days after Ms Jackson's disappearance, her son Joe, 23, who lived with her, had a conversation with Muir about his missing mother, the jury was told.
Mr Jackson said Muir told him that they had been discussing her Botox on the night she vanished.
"He said that she bought some Botox needles from one of her friends who was a chemist," the jury heard.
"That puzzled me because she didn't have any friends who were a chemist."
Mr Jackson said according to Muir, Ms Jackson then asked him to inject her with Botox but he refused because he was scared of blood.
"Then he said that my mother went upstairs into the bedroom and injected herself. She told him that she had done it before."
Muir then told him Ms Jackson came downstairs and her face looked wrinkled, and she had aged "really badly".
Mr Jackson continued: "Then apparently Adrian said she was an idiot for doing the Botox which caused the argument and then eventually my mother told him to leave and come back in a few days."
Mr Jackson asked Muir where his mother had gone, the jury was told.
"He said she went to a friend's house to stay for a while," the student and part-time shop worker said.
"Again, I was puzzled. There was no-one I could think of where she would stay because she had never done that before."
Later that day Mr Jackson and his brothers agreed to call in the police who started to make inquiries about her whereabouts.
He went to university the next day and when he returned, the house was cordoned off.
Ms Jackson, who had bi-polar disorder, had dated a number of men and her youngest son had described some of them as "horrible people".
Robert Woodcock QC, defending, told the court his client's case was that "one of them must have been, or is as likely as not to have been, the person with whom she disappeared on March 2".
The jury has been told Muir's phone and car were traced on the night of March 2 travelling from Chester-le-Street to the area of moorland where she was found.
Flowers were left in a plastic bag with the body and a fingerprint on the bag matched Muir, Andrew Robertson QC, prosecuting, has said.
Muir made three recordings on his phone in which he apparently confesses while intending to kill himself, the prosecution have claimed.
The case continues.