Michael Wynn, 63, was arrested early this morning at a £150 a month flat five days after the robbery at a bank in the Northern capital of Chiang Mai.
Thai Police said Wynn trained at a ‘Fitness Thailand’ gym before and after the robbery in the city centre last Wednesday.
Wynn, admitted the robbery, police said, after he was caught with most of the £12,000 cash stolen in his one bedroom apartment.
But he refused to give any further details of himself or the incident.
Police also took away three copies of the magazine Soldier of Fortune, one issue of Tactical Weapons, and 21 weapons videos.
Witnesses to the incident said they had seen Wynn drive past the bank several times on a red Honda Click motorcycle before the robbery.
One recognised him as a member of the Fitness Thailand gym in Icon Square, Chiang Mai.
Bank teller Suparat Rattanakot, who put the money in Wynn’s bag said: ‘Actually he did not say anything.
‘He just made the gestures, so we knew what he wanted.’
Wynn then fled on his Honda but was caught on several CCTV cameras.
Police Colonel Somsak Jantapung said: ‘He was recognized as a foreigner immediately from his build and skin colouring. Later his clothes, and his motorcycle provided more clues. We put him under surveillance at the gym and followed him back to his apartment.
‘We then applied for a warrant for his arrest and when we entered his apartment at the Loft Residence he let us in and admitted the robbery after we found the cash, and the helmet and shoes which were similar to those used in the robbery.’
Late today he was visited by a British Consular official.