An Iranian man was arrested for allegedly snatching a tourist's cash using a fake currency exchange trick.

Arash Esmi, 36, reportedly befriended Malaysian tourist Lai Jin Hao before offering to exchange his 100,000 baht into US dollars at the Avani Ratchada Hotel in Bangkok.

As Lai was about to show him the bank notes, the Iranian was said to have grabbed the wads of cash and fled on July 4.

He lodged a report with the Huai Khwang Police Station, who caught Arash as he was boarding a taxi in front of a McDonald's branch in Sathorn Nakhon on Sunday, July 13.

Police tracked the suspect down after CCTV footage from the area showed him riding the same taxi twice. They summoned the Thai cabbie, Boonmee Thuma, who claimed Arash had obtained his number to hire him occasionally as a chauffeur.

Police Lieutenant Colonel Chanaphat Suksawat of the Huai Khwang Police Station said: 'We told Mr. Boonmee to call us right away if the suspect got in touch again. Sure enough, he later reported that the same man had called, asking for a taxi to pick him up at the same McDonald's branch.

'Mr. Boonmee waited at the meeting spot in his car, while police monitored the area. When the suspect matching the physical description arrived, the cops stepped in to arrest him.'

Arash allegedly admitted to the robbery, saying he had already spent a portion of the money. He has agreed to return the full amount, and called his family to help him shoulder the payment.

Police said there was sufficient evidence of a criminal offence and charged him with robbery under Sections 78(3) and 66(2) of the Thai Criminal Code.

Police Colonel Prasopchok Eamphinij, superintendent of the Huai Khwang Police Station, said: 'I commend the investigation team for their swift arrest of the perpetrator. We urged anyone who may have been a victim of a similar incident to come forward and report to the police.'