The mother and stepfather of a 10-year-old girl have admitted to beating the child to death before dumping her body in a canal in Samut Prakan on June 10, police say.
Supaporn Montra, 31, and Wajaran Thadsawan, 35, have been charged with conspiring to kill the girl, Pornthip "Nong Rung" Kulanant, 10, and with concealing her body, said Charnthep Sesawech, commissioner of Provincial Police Region 1.
Pol Lt Gen Charnthep said Ms Supaporn, a maid, and Mr Wajaran, a public vehicle driver, admitted they often assaulted the girl after she came from Roi Et to stay with them at their home in Bang Sao Thong district of Samut Prakan during school breaks.
On June 10, the couple returned home to find Pornthip, a Prathom 5 student, dead and so they decided to wrap the body in a quilt before stuffing it inside a fertiliser bag and dumping it in Klong Phu Thao in tambon Si Sa Jorakae Yai, police said.
After disposing of the body, the couple fled to Saraburi where they were later apprehended by police.
Ms Supaporn said she hit her daughter because she was not obeying her and had a habit of lying. However, she insisted she did not mean to kill the girl, Pol Lt Gen Charnthep said.
Pol Lt Gen Charnthep said the couple had locked the girl up in the house while they were away from home. Forensic experts were running a test on the body to find out if the girl had been sexually violated prior to her death. Mr Wajaran denied he had sexually attacked the girl.
The couple were brought for a re-enactment at the crime scene Wednesday.
Pol Lt Gen Charnthep said investigators have gathered solid evidence and were confident they had a watertight case to forward to prosecutors.
Sukanya Montra, Ms Supaporn's younger sister, said Pornthip had lived with her in Roi Et. The girl usually spent her school break with her mother and stepfather.