The owner of a tiger zoo was among four suspected wildlife traders arrested during police raids in five provinces.
Police from the Natural Resources and Environmental Crime Suppression detained three men and one woman during searches at six locations in Bangkok, Pathum Thani, Nonthaburi, Ayutthaya and Suphan Buri provinces on Thursday.
The suspects were identified only as Bovornwit, 56, Suthep, 53, Sombat, 43, and Ms Pornthip, 25.
They were wanted on arrest warrants issued by the Nonthaburi Provincial Court on June 14 on charges of colluding in illegal trading in wildlife and illegal possession of protected wild animals.
During questioning, the suspects allegedly confessed to having acquired Indochinese tigers for sale. One of them was the owner of a tiger zoo in Suphan Buri, according to Thai media.
Thursday's raids follow the earlier arrests of three members of a wildlife trading gang when they delivered a tiger cub to an undercover agent in Bang Yai district of Nonthaburi on April 5.