NA KLANG, Thailand -- Weeping, grief-stricken families gathered Friday outside a Thai nursery where an ex-policeman murdered two dozen children in one of the kingdom's worst mass killings.
Thai King Maha Vajiralongkorn and Prime Minister Prayut Chan-O-Cha will later visit survivors of the attack that left at least 37 people dead, including the attacker's wife and child.
Around the small low-slung building, where only two days ago scores of preschool children played, officials in white uniforms laid a large floral wreath on behalf of the king.
A line of heartbroken parents placed white roses on the steps of the nursery as the baking sun bore down on them.
Buarai Tanontong's two three-year-old grandsons were among those killed at the nursery when the attacker burst through the door.
"I couldn't sleep. I didn't think that it would be my two grandsons," she said, clutching her inconsolable daughter's shoulder.
Overnight, coffins carrying the bodies of the victims arrived at a morgue in Udon Thani, the closest city to the rural district ripped apart by Thursday's three-hour rampage.
'Be a teacher in heaven'
Armed with a 9mm pistol and a knife, sacked police sergeant Panya Khamrab opened fire on the childcare centre in the northeastern Nong Bua Lam Phu province at about 12:30 pm (0530 GMT).
Following the attack, 34-year-old Panya fled the scene in a pickup truck to head home and murder his wife and son before taking his own life, police said, ending the killing spree around 3:00 pm.
In total, he killed 24 children -- 21 boys and three girls -- and 13 adults.
The dead include pregnant teacher Supaporn Pramongmuk, whose husband posted a poignant tribute on Facebook.
"I would like to thank all the support for me and my family. My wife has fulfilled her every duty as a teacher," husband Seksan Srirach wrote.
"Please be a teacher in heaven, and my child please take care of your mother in heaven."
A red carpet was installed around the nursery by officials before the royal wreath was laid, and later removed.
Social media users expressed criticism about the laying of a ceremonial carpet at a crime scene.
Drug addict
Flags on government buildings flew at half-mast on Friday in a gesture of mourning for one of the deadliest days in recent Thai history.
Nanthicha Punchum, acting chief of the nursery, described harrowing scenes as the attacker barged into the building in the rural Na Klang district.
"There were some staff eating lunch outside the nursery and the attacker parked his car and shot four of them dead," she told AFP.
She said the attacker smashed down the door with his leg and then started stabbing the children.
Local media reported that one child survived because they were sleeping hidden by a blanket when the attacker struck.
National Police Chief Damrongsak Kittiprapat told reporters that Panya, a former police sergeant, was suspended in January and sacked in June for drug use.
He said the attacker -- who used a legally purchased pistol -- had been due in court on a drugs charge, adding that Panya was in a manic state but it was unknown whether it was drug-related.
Witness Paweena Purichan, 31, said the attacker was well-known in the area as a drug addict.
She told AFP she encountered Panya driving erratically as he fled the scene.
"The attacker rammed a motorbike into two people who were injured. I sped off to get away from him," she said.
"There was blood everywhere."
Thai PM Prayut has ordered a rapid probe into the attack, and on Friday police interviewed witnesses and families.
The attack came less than three years after a soldier gunned down 29 people in a 17-hour rampage and wounded scores more before he was shot dead by commandos.
And less than a month ago an army officer shot dead two colleagues at a military training base in the capital Bangkok.
But while Thailand has high rates of gun ownership, mass shootings such as Thursday's are rare.