The Crime Suppression Division (CSD) on Tuesday launched a crackdown on a network that provided support for wanted gunmen, with raids on 21 premises in five provinces - Bangkok, Pathum Thani, Nonthaburi, Songkhla and Phatthalung.
CSD commander Pol Maj Gen Montree Theskhan said the operation involved about 80 officers from the Hanuman special operations unit and forestry police.
Targeted in the operation were members of a network of gunmen under Chamras Rakchan, alias Chui Khaochan, 45, who was No145 on the Royal Thai Police Office's list of wanted gunmen and was wanted for murder under a warrant issued by Pa Bon police in Phatthalung province.
On March 9, CSD police clashed with a group of crime suspects under Chamras. Pol Sr Sgt Maj Anant Meesang, a CSD officer, was killed and two other policemen wounded in the firefight.
Chamras and some of his men were later arrested while hiding in Bangkok.
The CSD still wanted to take action against people who had provided them with shelter and assistance while on the run. This led to the CSD crackdown on May 24, with 21 targets in Bangkok, Pathum Thani, Nonthaburi, Songkhla and Phatthalung.
A major target was the premises of Ruanrua Ngoenthong Tractor Company, a heavy equipment supplier in tambon Bang Krabue in Sam Khok district, Pathum Thani, which was owned by Sirachote Chotitreechai, alias Ko Sun, 48. He was suspected to have provided Chamras and his men with shelter and assistance while they were on the run prior to their arrest.
Armed with a warrant issued by the Criminal Court, a CSD team also searched Mr Sirachote's house at Laddaville 4 village in Nonthaburi's Bang Bua Thong district.
Mr Sirachote was detained and taken to CSD headquarters for questioning.
In the other provinces, eight people suspected to helping Chamras and his men were also detained for investigation. One of them, Teerasak Sakulpaet, 29, was arrested in Songkhla. In a search of his house police found 141 methamphetamine pills.
The nine were charged with providing help and shelter for people suspected of committing criminal offences in violation of Section 189 of the Criminal Code. Mr Teerasak was additionally charged with having drugs in possession with intent to sell.