The Singapore authorities have written to the Thai government, asking for its assistance in repatriating Canadian bank robbery suspect David James Roach to Singapore.

Roach was allegedly involved in a heist which took place on July 7 at the Standard Chartered Bank branch in Holland Village.

In a statement yesterday, the police said they have made a "mutual legal assistance request to the Thai authorities to seek their assistance to forward the evidence seized from the suspect to Singapore".

"If the Thai authorities are unable to return the suspect directly to Singapore, we will pursue the suspect's return from whichever country Thailand eventually decides to send the suspect to."

Singapore has no extradition treaty with Thailand.

Roach, 27, was arrested in Bangkok on July 10, three days after he allegedly took about $30,000 in cash from the StanChart bank.

It was the first successful bank robbery in Singapore in more than a decade.

On July 7 at around 11.30am, Roach is alleged to have walked into the StanChart branch, handed the teller a slip of paper with his demands and slipped away with about $30,000 in just minutes.

The same day, he fled Singapore for Bangkok. That evening, he checked into a shared dormitory room at the Boxpackers Hostel in the popular Ratchathewi district, initially paying for a two-night stay, before extending for another night.

He was nabbed by the Thai police, apparently in his upper bunk bed in the 12-bed dormitory.

To avoid detection, Roach starved himself and slimmed down to appear different from his passport photo, Thai police said.

Since his arrest, Roach has been held at an immigration detention centre in Bangkok.

The Thai police cancelled his right of stay in the country after Singapore issued a warrant for his arrest.

Danson Cheong