Australian man Simon Peter Carman pursued women on Threads before arrest over 17-year-old Thai girl’s death

Weeks before Australian man Simon Peter Carman allegedly murdered a Thai teenager who police say he had engaged for sex, he publicly told another woman posting provocative content online that she was “too fat” for him.

The remark was posted from Mr Carman’s public Threads account where the Perth man appears to have spent months using a copy-and-paste style of communication to contact women around the world before his dramatic arrest at Bangkok’s Suvarnabhumi Airport on Friday.

The 45-year-old was arrested just minutes before boarding a Jetstar flight to Perth.

Thai police allege Mr Carman killed 17-year-old Tunchanok Donhomla before placing her body inside a suitcase and abandoning it near railway tracks about 10 minutes from the hotel where he was staying.

Mr Carman has since been charged with murder, concealing a body, moving or destroying a body, and an offence relating to taking a minor aged between 15 and 18 for sexual purposes.

He denies murdering the teenager and has told police he acted in self-defence after allegedly being attacked during a dispute over payment.

The Nightly discovered Mr Carman’s unusual online activity in the months leading up to the alleged killing.

Across dozens of public replies dating back to January 2025, Mr Carman repeatedly commented beneath posts from women sharing intimate selfies and videos, frequently opening conversations with near-identical messages such as “Hello Gorgeous, how are you doing?” and “Where are you located?” before introducing himself, revealing his location and trying to move the conversations off-platform.

On June 4 this year when one woman posted a selfie asking: “Am i your type of girl?” Mr Carman bluntly replied: “Too fat.”

Three months earlier, on March 28, another woman asked: “i think i like you 😩 do you like asians?”, to which Mr Carman said “yes”.

On the same day, replying to another post whose original content is no longer available, he wrote: “I’m here, 45 !!.”

In numerous other public interactions, he told women he lived in Rockingham, about 50km south of Perth. In October he said that he had relocated to Thailand.

Meanwhile, Thai investigators allege Mr Carman met Ms Donhomla in the early hours of Thursday in Pattaya, a city known for its nightlife and tourism.

CCTV captured the pair walking hand-in-hand through the foyer of Mr Carman’s apartment building and into a lift at 3.34am.

Thai media reported Ms Donhomla had been hired to provide sexual services before an argument allegedly broke out over payment.

Investigators allege they had agreed on 1000 baht (about $43) but Mr Carman later offered only half that amount.

Around 18 hours later, CCTV allegedly captured Mr Carman leaving the building wheeling a large black suitcase before strapping it to a motorcycle and riding away.

The investigation began after one of Ms Donhomla’s friends reported her missing.

Police later traced her final known movements to Mr Carman’s accommodation before locating her body inside a suitcase in long grass beside nearby railway tracks.

Thai immigration authorities issued what local media described as a watch notice and Mr Carman was intercepted at Bangkok airport while allegedly attempting to leave the country.

Police have released video of Mr Carman in custody in which he expresses remorse to Ms Donhomla’s family but maintains the girl’s death was not his fault.

“I feel bad for what happened to your daughter,” he says in the recording.

“It was out of my control.”

He also urged the family to “tell other girls . . . to be careful”.

During police questioning, Mr Carman allegedly claimed Ms Donhomla threatened him with a knife and attempted to rob him before he acted in self-defence.

Asked about visible scratches on his neck and arms, Mr Carman told investigators they were caused by “spiders”.

The teenager’s devastated family publicly rejected his apology and called for him to receive the maximum punishment if convicted.

Her father, Thongchai Donhomla, described his daughter as a hardworking young woman who regularly helped support the family, while her stepmother said she wanted Mr Carman to be executed.

Family members said Ms Donhomla had travelled to Pattaya for the first time only days earlier with a friend.

Mr Carman is understood to have been born in Ballarat before growing up in Jerramungup, about 440km south-east of Perth. He later lived in Albany before settling in Rockingham.

Before leaving Australia, Mr Carman had spent much of the previous decade living in an industrial unit complex in Rockingham while surviving on a disability pension and compensation payments linked to injuries he sustained as a truck driver.

People who knew Mr Carman told The Australian he suffered significant back injuries, had a metal rod in his spine and relied on strong pain medication.

He largely kept to himself, they said.

The Nightly has confirmed he also previously lived in Perth’s southern suburb of Casuarina. Neighbours there said they were shocked to learn of the allegations.

A woman who answered the door at a property listed in Mr Carman’s name confirmed he no longer lived there, although his mail still arrived at the address.

According to The Australian, Mr Carman relocated to Thailand about eight months ago, reportedly seeking a cheaper lifestyle and medical treatment after local surgeons refused to operate on his back.

In Thailand, he reportedly rented a modest apartment for about A$100 a week, spent time swimming and walking, and brewed ginger beer.

Former acquaintances quoted by the Daily Mail described Mr Carman as socially awkward and said he had spent years travelling between WA and Thailand before relocating there.

Mr Carman remains in custody in Pattaya while Thai authorities continue investigations.

If convicted of murder in Thailand, he could face life imprisonment or the death penalty.