The Frenchman, Henry Richer, 54, gave his associate only 2000 baht on September 28 as commission on a property deal where the land sold for two million baht.
As a result, the unhappiness of Boonpring Kaewnagdee was such that he schemed against Mr Richer, Phuket's Police Commander, Major General Ong-art Phiwruangnontsaid, said at Phuket City Police Headquarters.
He offered to join Mr Richer again in taking some ya ice, then when the time came for them to share the drug, he turned up and surprised Mr Richer with a gang and a gun.
A man who said he was a policeman joined the group and told Mr Richer that he would be arrested over the drugs unless he paid the gang 300,000 baht for his freedom.
Mr Richer was handcuffed and gave the gang three ATM cards and passwords. The gang later removed 490,000 baht from the accounts.
On October 23, Mr Richer went to Vichit Police Station to report what had happened.
Police arrested Khun Boonpring later that day and have since also arrested policeman Pichan Keawkongtam and Kanatnan Patan.
Khun Boonpring has made a full confession, say police. Khun Kanatnan is alleged to be a collector of bribes from Patong businesses.
Warrants have been issued for the arrests of three other men. Investigations are continuing.