At least 36 people, most of them children, were killed by an ex-policeman at a preschool daycare center in Thailand’s northeast on Thursday, police and hospital officials said.

The attack took place in the Na Klang area of Nong Bua Lamphu province in the early afternoon.

Authorities said 22 of those killed were children.

Police identified the killer as 34-year-old Panya Kamrab, a former police sergeant who was dismissed from service in January. According to a police report, he was sacked after being found in possession of narcotics.

Panya is thought to have gone to the daycare center to find his son but when he failed to find the boy he began shooting. He then returned home, where he killed his wife and child.

Video footage and images shared on social media showed the distraught relatives of the victims standing beside ambulances outside the daycare facility as police and rescuers dealt with the aftermath of the attack.

On Friday morning, royal and government representatives in white, military-style coats stood in lines to lay wreaths at ceremonial tables in front of the Young Children’s Development Center’s main door. They were followed by weeping family members, who gathered their hands in prayer before laying white flowers on the wooden floor.

Many relatives were gathered in front of the child care center to start the process of claiming compensation and psychologists were also sent to the site to help them. Seven of the 10 people who were wounded were still hospitalized Friday.