It was a crackdown on trafficking of Rohingya and other migrants, starting in Ranong five years ago, that put key suspect Lt-General Manas Khongpaen in charge, and later taught him to know how to make profit from the illicit trade of humans.
Then a colonel, Manas headed an Internal Security Operations Command (ISOC) mission in Ranong.
It led a coalition of 17 government agencies in an operation, codenamed "Phithak [protect] Andaman", to monitor movement of and intercept Rohingya and other migrants smuggled through Ranong, mainly on land routes.
From 2010, the operation led Manas to know two key traffickers based in Ranong who had been running a number of illegal businesses - including trafficking of illegal migrants, especially in the first-phase of the Phithak Andaman mission - from November 2010 to April 2011.
The mission's militarised policies, some of which were notably clandestine, included setting up a civilian scouts network to monitor movement of groups of strangers and to notify officials of their discovery. At the same time they indoctrinated local residents with patriotism and other basic military training and jungle trekking. They also set up communications stations and provided two speedboats for use in auxiliary coastal maritime patrols.
To deal with migrants on board fishing trawlers or other ships, patrols and monitoring were established along five islands from Ta Krut to Khang Khao off the Ranong coast. A key clandestine policy was to convince boat people not to enter Thai waters while providing food, freshwater and fuel for a sea trek - enough for up to 20 days, which would take the vessels to a neighbouring country.
With the clandestine nature of the Phithak Andaman mission under his direct command, Manas was able to keep both his work and the trafficking a secret to outsiders for all five years covering later stages of the mission. Well-liked for his solid charisma and high-disciplined character, Manas became popular with local residents.
He was often invited to preside over ceremonies and was chief adviser to Ranong Football Club.
Soon after being promoted to the rank of major-general, Manas applied for senatorial election but lacked a key candidacy qualification.
He was later appointed to a key position in Songkhla and was heard telling guests at a party about his next plan to be based in his home province of Nakhon Si Thammarat. He said he wanted to open bullflighting dens - even though his original intent was to be based permanently in Ranong.