An American accused of running a passport-forgery ring in Bangkok confessed to dismembering -- but not murdering -- a man found in his freezer, Thai police said Saturday, as detectives continue to piece together details of the macabre crime.

The 63-year-old suspect, who police initially struggled to identify because of his numerous passports, was arrested one week ago alongside two other Americans accused of producing fake travel documents from their crime den in the Thai capital.

Police also found guns, drugs and the bagged body parts of a foreigner in their freezer.

Herbert La Fon, described as the gang's ringleader, allegedly opened fire on police during the raid before the trio was handcuffed and detained.

‘He admitted only that he dismembered the body but said he had no involvement in murdering the Hungarian man,’ Bangkok's police chief Sanit Mahathavorn told reporters Saturday.

‘I cannot disclose the details, but I can say that his testimony was useful. As for (his claim) that the motive of the killing was debt, police are not really convinced by this,’ said Sanit, adding that officers were up until 3am interrogating the American.

It was not immediately clear what La Fon's explanation for possessing or cutting up the corpse was. Police have stressed that his story keeps changing.

It is also not uncommon for suspects to later retract confessions made in Thai police custody, where many have alleged being beaten by officers.

Forensic experts are still working to identify the man found in the freezer but said they believe he was Hungarian and middle-aged.

‘Initially we think he was Hungarian. We don't know the time of his death because the body had been frozen for a long time,’ Udomsak Hunvichit, head of Chulalongkorn Hospital's forensic department, told local broadcaster Channel 3.

The gruesome case has gripped the Thai public as it provides a glimpse into Bangkok's shadowy underworld, long a haven for foreign criminals and fugitives.

Little is known about the three men other than that La Fon was wanted by the FBI in 1979 on charges of credit card fraud.

A US Embassy official confirmed American law enforcement agencies are assisting with the case.

Thailand is a hub for a fake documents trade that has helped shield countless criminals and migrants from local and foreign authorities.

In February Thai police arrested an Iranian man known as ‘The Doctor’ who crafted pristine passports from his home in a Bangkok suburb and sold the documents to thousands around the globe -- including gangsters, rebels, refugees and migrant workers.