A former ranger was arrested on Saturday for allegedly murdering his wife and daughter at their house in a valley in Nan province, police said.
Prompipat Promkesa, 43, denied the charges.
Prompipat used to be a ranger based in Pattani and had left the service two years ago.
The bodies of Sriwan Yod-on, 45, and Pitchayada Promkesa, 7, were found in the bedroom of their house in Ba Pha Nam Yoi in Tambon Phaya Kaew, Chiang Klang district, on Thursday evening. A relative visited Sriwan but when she did not answer the knock, she opened the door and found the bodies.
Police said both victims were shot in the head while lying on the bed and their bodies were covered with two blankets.