Relatives mourn during a ceremony for those killed in the attack on the Young Children’s Development Center in the rural town of Uthai Sawan, northeastern Thailand Friday. Sakchai Lalit/Associated Press

UTHAI SAWAN, Thailand — Relatives wailed and collapsed in grief before the small coffins of children Friday after a fired police officer stormed a rural Thai day care center at naptime and massacred 36 people.

At least 24 of the dead were children, mostly preschoolers. The grisly gun and knife attack a day earlier was the deadliest mass killing in Thailand’s history, leaving virtually no family untouched in Uthai Sawan, a small rural community nestled among rice paddies and palms.

“I cried until I had no more tears coming out of my eyes,” said Seksan Sriraj, 28, whose wife was a teacher at the Young Children’s Development Center and was due to give birth this month.

Across the country, flags were lowered to half-staff and schoolchildren said prayers to honor the dead, while at the site of the attack, about 85 miles from Laos, a stream of people, including Prime Minister Prayuth Chan-ocha, left flowers. The wall outside the small, one-story day care center was lined with bouquets of white roses and carnations, along with juice boxes, bags of corn chips and a stuffed animal.

Relatives crowded the grounds of a nearby Buddhist temple to receive the dead after their autopsies. Some screamed as the small, white coffins were opened. Others fainted and were revived with smelling salts.

“It was just too much. I can’t accept this,” said Oy Yodkhao, 51, a rice farmer whose 4-year-old grandson Tawatchai Sriphu was among the dead.

Som-Mai Pitfai collapsed at the sight of her 3-year-old niece’s body.

“When I looked, I saw she had been slashed in the face with a knife,” the 58-year-old said, holding back tears after being revived by paramedics.

Elsewhere, King Maha Vajiralongkorn and Queen Suthida visited two hospitals where some of the 10 people who were wounded were being treated.

A distraught woman is comforted outside the site of an attack at a day care center, Thursday in Nongbua Lamphu. Mungkorn Sriboonreung Rescue Group via AP

Police identified the attacker as Panya Kamrap, 34, a former police sergeant fired earlier this year because of a drug charge involving methamphetamine. He had been due to appear in court Friday.

Authorities believe Panya may have been triggered by an argument with his wife. He took his own life, police said, after killing his wife and son at home.

“As of now, the police assume that he became stressed because he was afraid that his wife would leave him,” National police chief Gen. Dumrongsak Kittiprapas said.

In interviews with Thai media, Panya’s mother said there was tension between her son and his wife, and talking with 3Plus News, she said he was stressed by debt.

An initial autopsy of Panya did not detect any dangerous drugs, police said. A second autopsy was planned.

Children at the day care center had been taking an afternoon nap at the time of the attack, and photos taken by first responders showed their tiny bodies still lying on blankets. In some images, slashes to the victims’ faces and gunshots to their heads could be seen. An employee of the center told a Thai TV station that Panya’s son had attended the day care but hadn’t been there for about a month.

In an interview with Amarin TV, Satita Boonsom, a worker at the center, said staff locked the building’s glass front door after seeing the assailant shoot a child and his father out front. But the gunman shot and kicked his way through.

Officials enter the site of an attack at a day care center, Thursday, in Nongbua Lamphu, Thailand. TPBS via AP

Satita said she and three other teachers climbed the center’s fence to escape and call police and seek help. By the time she returned, the children were dead. She said one child who was covered by a blanket survived the attack, apparently because the assailant assumed he was dead.

The center usually has 70 to 80 children, she said, but there were fewer at the time of the attack because the semester had ended for older children and monsoon rains prevented a school bus from operating.

“They wouldn’t have survived,” she said.

One of the youngest survivors was a 3-year-old boy who was riding a tricycle close to his mother and grandmother when the assailant began slashing them with the knife. The mother died from her wounds, and the boy and grandmother were being treated at hospitals, according to local media.

Mass shootings are rare but not unheard of in Thailand, which has one of the highest civilian gun ownership rates in Asia. The rate is 60 times the level in Japan, though still a fraction of the rate in the U.S, according to a 2017 survey by Australia’s GunPolicy.org nonprofit organization.

Thailand’s previous worst mass killing involved a disgruntled soldier who opened fire in and around a mall in the northeastern city of Nakhon Ratchasima in 2020, killing 29 people and wounding nearly 60 others.

In 2015, a bombing at a shrine in Bangkok killed 20 people.

Associated Press writers Chalida Ekvitthayavechnukul, Elaine Kurtenbach and Grant Peck in Bangkok and Kim Tong-hyung in Seoul, South Korea, contributed to this report.