Eight suspects for the mass killing in Krabi province were handed over to police on Friday after their detention by soldiers was due.
The Royal Thai Army at the 15th Infantry Battalion in Khlong Thom district turned over Surikfat Bannopwongsakul, alias Bang Fath, and seven other alleged killers to national police chief Chakthip Chaijinda at the provincial police headquarters in Muang district.
All had been arrested by police on Saturday and could be held in military custody under Section 44 of the interim constitution for no more than seven days.
All were interrogated again by police and will be sent for detention at the Krabi prison later on Friday.
They were charged with conspiring to murder others, attempting to murder others, forcing others to sign documents regarding their title deeds, illegally possessing the firearms of others, illegally carrying firearms, illegally dressing in military-style uniforms, falsely identifying themselves as military officers, and operating a criminal network.
Mr Surikfat and Mr Khomsan in particular face additional charges for colluding to commit premeditated murder and attempting to commit premeditated murder because police believed they had pulled the trigger, killing the eight victims and injuring three others.
The massacre occurred at the house of village head Worayut Sanglang in Ao Luk district on July 10. Police pointed to the conflict over the land title deeds between Worayut and Bang Fath as the motive.
Pol Gen Chakthip promised a quick wrapup of the case before sending the report to prosecutors to file lawsuits against them.