Anthony Albanese has discussed joint anti-crime efforts during a rare visit by Thailand’s leader, just hours after further details emerged in the case of a Perth man accused of murdering a young woman at the popular tourist destination of Pattaya.

The PM and Anutin Charnvirakul met in Canberra on Wednesday, the same day it was revealed in a police autopsy that 17-year-old Tunchanok Donhomla, who was allegedly killed by 45-year-old Perth man Simon Carman in June, died of suffocation.

Both Prime Ministers made renewed commitments to closer police cooperation during an address at Parliament House, with Mr Albanese noting “combating transnational crime” as the first area the nations could “work more closely across”.

“We discuss how we can make an even stronger contribution to a peaceful, stable, and prosperous region. To do so, we’ll work more closely across a range of areas. One is combating transnational crime,” Mr Albanese said.

While Mr Albanese declined to say whether he asked his Thai counterpart to spare the life of the accused Australian killer, a leading expert said it would have been premature for him to do so.

One of Australia’s leading international law experts Donald Rothwell said it was “too early” for the Prime Minister, or even Foreign Minister to intervene in such a case.

Mr Carman has been charged but has not yet stood trial after he was arrested at the Suvarnabhumi International Airport in Bangkok while trying to board a Jetstar flight to Perth after the teen was found stuffed naked inside a suitcase dumped near railway tracks.

He is being held in Pattaya Remand Prison on four offences, including moving a body, taking a minor for sexual purposes, and murder. He could face the death penalty or life imprisonment if convicted.

It comes as Thai police revealed to the ABC on Wednesday that they will hand the case over to prosecutors this week after concluding their investigation into the death of the teen, known to friends as “Nong Cake” or “Cake”, near Pattaya Beach in the early hours of June 25.

While Australian PMs have previously made representations for Australians facing death penalties abroad, Professor Rothwell said diplomatic representation is reserved for the end of the legal process.

When asked on Wednesday, Mr Albanese’s office declined to comment on if he had, citing ongoing court proceedings.

“We’re still at very early days in this particular matter and it would be exceptional for the Prime Minister to have raised this with his counterpart,” Professor Rothwell said.

“It would be exceptional, in my experience.”

Professor Rothwell said if a death penalty was to be applied on conviction the “normal course of events” would be that the Foreign Minister would first get involved.

“The matter would escalate from DFAT, consular, embassy officials — up to the level of the foreign minister,” he said.

“It’s only quite late in these processes that the Australian Prime Minister becomes involved.

“And that, more often than not, is in and around the time when ultimately a date for an execution may well be set, or all of the appeal processes have been exhausted.”

During his first term in 2023, Mr Albanese had made representations for two Australians in Vietnam but only after they were sentenced to capital punishment.

Both were eventually granted clemency, with the PM saying at the time that “we make representations, we do it diplomatically and we always hope for positive outcomes in the interests of Australian citizens”.

In a joint statement on the issue released after the meeting, the leaders committed to continued efforts to target crimes such as human trafficking, financial fraud, money laundering, cybercrime, scams and the illicit trade of narcotics and tobacco.

Mr Charnvirakul, who is the first Thai leader to visit Australia in 14 years, also led his public remarks with stronger anti-crime efforts between the two nations.

“We agreed to strengthen our joint response to traditional and emerging security challenges, particularly transnational crime, and to advance our cooperation through existing and future security frameworks,” Mr Charnvirakul said.

In their signed joint statement, the pair agreed to “strengthen law enforcement capabilities and victim-centred approaches” to counter “trafficking in persons in all its forms”.

“Including through the ASEAN–Australia Counter Trafficking Program, Thailand’s Countering Trafficking in Persons Centre of Excellence, and the Anti-Trafficking in Persons Centre.

The superintendent at the Pattaya City Police Station, Colonel Anek Srathongyoo, on Wednesday confirmed in an interview with the ABC that collected DNA from Mr Carman had “matched it to DNA found on Cake’s body”.

The suitcase had been found more than 4km from Mr Carman’s Jomtien apartment complex in the Thai city of Pataya.

The teen was last seen alive on CCTV around 3.30am on Thursday, June 25 entering the complex hand-in-hand with Mr Carman.

“The autopsy report said that Cake had a brain injury and she suffocated. She had no other injuries,” the police Colonel told the ABC.

Mr Carman is accused of leaving the rear of the complex dragging a suitcase containing her body about 9.25pm that night.

He is accused of strapping the suitcase to the rear of a motorcycle, dumping it near railway tracks, before returning to his complex around 35 minutes later.