The final text message exchange between accused Thai suitcase killer Simon Carman and his mother has been revealed.

Victorian-born Carman is being held in a Pattaya jail over the death of 17-year-old Tunchanok Donhomla, whose naked body was found in a black suitcase next to a railway line last month.

Mr Carman is expected to plead not guilty to the murder of the teenager, claiming he acted in self-defence.

After seeing her son pictured in media coverage of the death of the teenager, the accused’s WA-based mother, Wendy Carman, sent him a frantic text message, a police source told the Daily Mail.

She initially believed CCTV footage appearing to show her son had been generated using AI as part of a scam.

According to the Daily Telegraph, the first message Mr Carman saw after authorities returned his mobile phone was from his mother.

“There is a period of time after his arrest but before the first court appearance, when a judge decides whether a suspect gets bail or is moved to a detention centre,” a police source said.

“During those hours, if it’s no longer needed as part of police evidence, you can use your phone.”

The source added that Mr Carman became emotional after reading the contents of his mother’s message.

“He broke down and said, ‘Even my mum’s heard about it,”’ they added.

“He got very upset when he read that message from her, and I think the reality of the situation finally sank in.

“He had given his statement in a very matter-of-fact way before that.

“He was even calm when he explained he had folded her body into a suitcase and put it away in his bathroom.”

Mr Carman has been charged with intentional murder, concealing a corpse, moving or destroying a corpse, and abduction of a minor for indecent purposes, according to Thai police.

It is alleged Ms Donhomla left Pattaya Beach Road with Carman at about 3.30am on June 25 after striking up a conversation with him.

In the early hours of Thursday, they returned to his apartment, where she was strangled and killed, police said.

A friend reported her missing on Friday afternoon.

The victim’s father, 46-year-old Thongchai Donhomla, previously said he is struggling to come to terms with the loss.

“I am deeply saddened. My daughter had no mother, so whenever she wanted anything, she would find a way herself, and she always helped me too,” he said.

Meanwhile, the teen’s stepmother called for her murderer to be “executed” if found guilty.

“I don’t know what else to say… I just want him to face the full consequences,” she said.