A police officer has confessed to his involvement in the murder of Phra Bandit Supanthito, the police spokesman said on Friday.
Pol Lt Gen Prawut Thawornsiri said that Chanchai Soisangwan had admitted to being a member of the team that shot to death the abbot of the Tor Si Siad forest monastery in Muang district in Udon Thani province on March 1.
The spokesman did not go into details of the confession.
Pol Snr Sgt Maj Chanchai would be moved from the Bung Kan police station to the Udon Thani provincial police office for further interrogation after Lao authorities arrested him in the Lao province of Borikhamxay, opposite Bung Kan.
Laos handed the man over to Thai authorities on Thursday.
The officer in charge of drug suppression could be a key for investigators who are hoping to close in on the mastermind, believed to be a well-known person in Udon Thani.
Pol Snr Sgt Maj Chanchai is said to have been hired to shadow the monk days before he was slain. The officer allegedly picked up gunman Panja Chareesaen and pointed out the monk for the shooter on the day pf the slaying.
Police inspector-general Pol Lt Gen Suchart Theerasawad confirmed the confession and said the mastermind paid Pol Snr Sgt Maj Chanchai 300,000 baht.
Phra Bandit, 48, was known among followers as the "doctor monk" due to his background as a physician in several hospitals in Udon Thani.
The investigators' main theory so far is that the person who ordered the slaying did so after seeing a close female friend frequenting the temple for meditation.