Originally Published: 06 OCT 22 03:56 ET

Updated: 06 OCT 22 11:56 ET

By Kocha Olarn, Hannah Ritchie and Heather Chen, CNN

(CNN) -- Thailand recoiled in horror Thursday after at least 36 people were killed, at least 24 of them children, in a massacre at a child care center in northeastern Thailand that is believed to be the country's deadliest incident of its kind.

Authorities immediately launched a manhunt for the suspected attacker, later identified by Thailand's Central Investigation Bureau (CIB) as Panya Kamrab, a 34-year-old former policeman involved in an ongoing court case for allegedly selling drugs.

Investigators later confirmed he had killed his wife and his stepson before taking his own life. The attacker's wife and children are included in the current death toll.

The suspect had appeared in court in Nong Bua Lamphu province hours before "opening fire while the kids were sleeping," according to Maj. Gen. Jirapob Puridet of the CIB. The former officer was dismissed from duty and "charged with selling narcotics" last year, Puridet told CNN.

His 2-year-old stepson was enrolled at the center he attacked Thursday, but was not present while the attack was carried out, according to a local police chief.

"(The shooter) went to look for his two-year-old son, but the boy was not there ... so he started shooting as well as stabbing people at the nursery," police spokesperson Maj. General Paisan Luesomboon told CNN.

Kamrab then "managed to get into a room where 24 kids were sleeping together," killing all but one of them.

"He also used a knife to stab both children and staff at the center," Luesomboon said.

One of the center's teachers described a horrific scene to local media, explaining that the attacker entered the center around noon, while two other staff members were having lunch.

"I suddenly heard the sound just sounded like fire crackers. So I looked back [and] the two staffs just collapsed on the floor," the teacher said.

"Then he pulled another gun from his waist...I didn't expect he would also kill the kids," they said.

The teacher also said that the attacker was also carrying a second gun, as well as a knife, which he used to fatally stab another teacher, who was eight months pregnant.

One eyewitness told Reuters she believed the attacker was coming to pick up his child. When he arrived to the center, he "didn't say anything," and "shot at the door while the children were sleeping," she said.

Most of the deaths were the result of "stabbing wounds," Luesomboon told CNN. A statement earlier on Thursday from Prime Minister Prayut Chan-o-cha's office office had referred to the incident as a mass shooting.

The massacre took place at the Child Development Center in Nong Bua Lamphu province's Uthaisawan Na Klang district, according to a statement from the Prime Minister, who called the incident "shocking" and expressed his condolences to the families of the victims.

The province, located approximately 540 kilometers (around 335 miles) northeast of Bangkok, is a largely peaceful and quiet area, and is not known for violence.

Chan-ocha will travel to the province on Friday to meet with families of the victims, according to a statement from his office.

Gun ownership in Thailand is relatively high compared with other countries in Southeast Asia.

There were more than 10.3 million civilian owned firearms in Thailand, or around 15 guns for every 100 people, according to 2017 data from the Switzerland-based Small Arms Survey (SAS). Approximately 6.2 million of those guns are legally registered, according to SAS.

Thailand ranks as the Southeast Asian country with the second-highest gun homicides after the Philippines, according to the Institute for Health Metrics and Evaluation (IHME) at the University of Washington's 2019 Global Burden of Disease database.

Mass shootings in the country, however, are rare but a 2020 incident saw a soldier kill 29 people in a shooting spree that began at a military site and then sent shoppers hunting for cover after the gunman entered a mall.

The incident sparked international condemnation.

In a statement, UNICEF said it was "shocked" by the tragedy and sent its condolences to the families affected. It condemned the attack, saying: "No child should be a target or witness of violence any where, anytime," adding, "Early childhood development centers, schools and all learning spaces must be safe havens for young children to learn, play and grow during their most critical years."

UK Prime Minister Liz Truss said in a tweet that she was "shocked to hear of the horrific events," and said that her "thoughts are with all those affected and the first responders."

"The UK stands with the Thai people at this terrible time," she said.