A 39-year-old factory machinist was arrested on charges of illegally making, modifying and selling guns when police raided his room at a workers' dormitory in Pak Kret district, Nonthaburi.
Crime Suppression Division police with a warrant from the Criminal Court searched the dormitory at a lathe plant in tambon Khlong Khoi of Pak Kret district around 6am on Thursday.
They arrested Prajak Phoonphian on a warrant alleging collusion in illegally producing or modifying guns, importing or selling firearms and possessing firearms without permission.
He was sleeping when police arrived to arrest him.
A search of his room found pen guns, blank-firing guns and gunsmithing tools, according to police.
Pol Col Veeracharn Khunchaikaew, superintendent of the CSD sub-division, led the operation.
He said investigators followed up on information about a gang illegally producing and selling firearms online and evidence pointed to Mr Prajak's involvement.
During questioning, Mr Prajak said he worked at the factory but did not earn enough to make ends meet due to the rising cost of living, so he worked with some friends in producing pen guns, BB guns and blank guns. The guns were sold to a trader who later sold them online.
Mr Prajak admitted he had been making guns for two years and had sold more than 100 to the trader.
He said he used the skills he learned at technical college and used the machines and equipment at the factory to produce the guns when nobody was there.
Each pen gun cost about 400 baht to make and he sold them for 1,100 baht each to the trader, who resold them for 1,600 baht each.
The cost of making the blank guns and BB guns was 8,000-9,000 baht a piece and once fitted with barrels they were sold at 16,000-20,000 baht each, depending on the gun.
CSD teams also went to another 15 locations in Nakhon Sawan, Phetchabun, Ubon Ratchathani, Amnat Charoen, Chon Buri, Samut Prakan, Ayutthaya, Ang Thong, Nonthaburi and Nakhon Pathom provinces to arrest other alleged members of the illegal gun dealing network, Pol Col Veeracharn said.