Police on Wednesday arrested four men for allegedly shooting dead a forest protection officer at Sap Langka Wildlife Sanctuary in Lop Buri's Lam Sonthi district.
Pol Maj Gen Thanayuth Wuthicharasthamrong, deputy commissioner of Provinical Police Region 1, overseeing the Central Plains provinces, said the arrested men were residents in tambon Kut Ta Phet of Lam Sonthi district.
The men, alleged poachers, were identified as Thes Netsangsri, Boonlue Saikhun, Warawut Thuasanit and Boonlome Jullanak.
Pol Maj Gen Thanayuth did not disclose how police apprehended the four.
He said they were caught in an area near the wildlife sanctuary and admitted to killing Khuan Chaiprasert, the chief forest protection officer at the wildlife sanctuary.
He said some of the suspects admitted opening fire on forest protection officers to evade arrest while hunting illegally in the forest.
Police on Wednesday returned to the scene of the killing to collect more evidence, Pol Maj Gen Thanayuth said.
The arrests were made after Prime Minister Prayut Chan-o-cha on Tuesday ordered local police to bring Khuan's murderers to justice as soon as possible.
Gen Prayut also expressed his deep condolences to the dead man's family, praising him for his sacrifice to protect nature.
Khuan along with his two subordinates were on patrol in the forest on Sunday when they came under fire.