Chakkraphat Wichitvaidya, a local police official, told Reuters autopsies showed the children had been slashed with a large knife, sometimes multiple times, and adults shot.
He said police were investigating the motive, while suspecting that Panya could have been triggered by stress.
“I don’t know (why he did this), but he was under a lot of pressure,” Panya’s mother told Nation TV, citing debts her son had run up and his drug taking.
There were about 30 children at the center when the attack began, which was fewer than usual as heavy rain had kept many people away, said district official Jidapa Boonsom.
The attacker forced his way into a locked room where the children were sleeping, Jidapa said. Three boys and a girl who survived the attack were being treated in hospital, police said.
The massacre is among the worst involving children killed by one person. Anders Breivik killed 69 people, mostly teenagers, at a summer camp in Norway in 2011, while the death toll in other cases include 20 children at Sandy Hook Elementary School in Newtown Connecticut in 2012, 16 at Dunblane in Scotland in 1996 and 19 at a school in Uvalde, Texas, this year.
Gun laws are strict in Thailand, but gun ownership is high compared with some Southeast Asian countries, and illegal weapons are common, with many brought in from strife-torn neighbours in the region.
