Children lay napping after eating lunch on a rainy day in their childcare centre in north-east Thailand on Thursday, but their dreams soon turned to a gruesome nightmare during the country’s deadliest mass killing of civilians by a lone gunman. A former police officer entered the Uthai Sawan Child Development Centre in Nong Bua Lam Phu province and began shooting and stabbing. He later died by suicide, leaving at least 36 dead. Among the dead lay 21 boys and three girls. Thailand’s Central Investigation Bureau (CIB) identified former police officer Panya Khamrab, 34, as the killer, but said his motivation was not known. The north-east region is one of Thailand's poorest and relies on agriculture for income. After the nursery attack, Panya escaped by driving away, allegedly killing people as he fled. Later he killed his wife and child before taking his own life. Terrified parents ran to the neat, one-storey building to find out if their loved ones had survived. The air rang loudly with sirens, the cries of the wounded and a media scrum. “My wife was due next month,” the husband of a pregnant teacher stabbed to death told Thai television, tears streaming down his face. “I will never get to see my wife with our child.” Some children's unwashed lunch dishes still lay on tables, scattered with leftover vegetables and rice. Panya was dismissed from the police force last year over methamphetamine possession, intoxication and being a public nuisance, police said. The CIB's Maj Gen Jirapob Puridet told<i> </i>CNN that the gunman had also been “charged with selling narcotics” last year. Methamphetamines are popular throughout Thailand and known as “ya baa” — crazy medicine. They are highly addictive, illegally manufactured drugs that can induce hallucinations, paranoia and fears of persecution. Panya began “opening fire while the kids were sleeping”, Maj Gen Jirapob said. He wielded a 9mm handgun — legally purchased for personal use — and a knife, National Police Chief Gen Damrongsak Kittipraphat said at a news conference. Investigators said Panya began his day in Uthai Sawan town, 500 kilometres north-east of Bangkok near the Mekong River, which forms part of Thailand's border with Laos. In the morning, he went to a local court to hear an update about his drug case. The court told him to appear again the next day, Police Chief Damrongsak said. Panya left the courthouse and drove to the nearby Uthai Sawan Child Development Centre, armed and ranting. “He was already stressed, and when he couldn't find his child, he was more stressed and started shooting,” police representative Paisal Luesomboon told ThaiPBS media. “He started shooting, slashing, killing children at the Uthai Sawan day care centre.” A witness said: “It's really shocking. We were very scared and running to hide once we knew it was a shooting. So many children got killed.” Prime Minister Prayuth Chan-ocha announced: “I have ordered the police chief to travel to the scene immediately, to take necessary actions and all involved parties to provide immediate relief to all affected people.” The prime minister reportedly plans to fly to the small town on Friday to meet relatives and survivors. Investigators also want to find out why Panya was initially so obsessed with finding his son and why he became so angry that he vented his rage with bullets and sharpened metal. Meanwhile, when local hospitals asked the public to urgently donate blood to keep severely injured survivors alive, people lined up to contribute. Mass shootings of civilians are rare in Thailand. Thailand's previous biggest mass shooting occurred in 2020, when an army gunman in a Korat city shopping mall killed at least 20 people before snipers shot him dead.