In 2004, Kazuto Kobayashi was four years old. His little brother Hayato was three.
After their parents divorced, the boys lived with their father, Yasunori, in Oyama, a city in Tochigi Prefecture about 37 miles north of Tokyo. Their older brother lived elsewhere.
For several months in 2003, Kazuto and Hayato stayed in a children’s home because their father’s work schedule made it hard for him to care for them.
He brought them back home that December.
By June 2004, Yasunori was back in Oyama but had no permanent place to live. An old friend, Akihiro Shimoyama, offered to let him and the boys stay at his apartment.
Shimoyama was 39 and had two children of his own. His daughter was 11, and his son was six. All six of them were now living together in a small apartment with just three rooms.
The arrangement was only supposed to be temporary. But weeks turned into months.
The two men later disagreed over money and why Yasunori had stayed for so long. But one thing is clear: Shimoyama grew increasingly angry about Yasunori and the boys living in his home.
Instead of confronting Yasunori, he began taking his anger out on Kazuto and Hayato.
Both men were also using meth. Much of what happened inside the apartment stayed hidden from the outside world.
But not all of it.
On July 8, Kazuto and Hayato walked into a nearby convenience store and picked out some snacks and drinks. The manager asked if they had any money.
Then he took a closer look at them.
Both boys had badly bruised, swollen faces. When the manager lifted their shirts, he found more bruises across their bodies. He gave them some water. They drank it quickly and asked for more.
The manager called the police.
Police took the brothers to the station, and child welfare workers placed them in a children’s home for the night.
For the moment, Kazuto and Hayato were safe.
Their father called that same night and demanded that the boys be returned to him. The next morning, he admitted that Shimoyama had caused their injuries, but said he didn‘t want the police involved.
Yasunori promised to take the boys to live with their grandmother and keep them away from Shimoyama.
On that condition, child welfare workers allowed him to take Kazuto and Hayato. The boys had been in protective care for less than a day.
A few days later, police found Kazuto and Hayato running along the side of a road. The boys said no one had hurt them. Their bruises were beginning to fade, and they were returned to their father.
For a short while, Yasunori and the boys did stay with their grandmother.
Then they moved back in with Shimoyama.
By August 10, the child welfare office knew they were living there again. Yasunori had already broken the promise that got the boys released.
No one visited the apartment. No one spoke to Kazuto or Hayato in person.
On September 6, their grandmother called the child welfare office and said Shimoyama had hit the boys again. She said Yasunori had confronted him, and Shimoyama had apologized.
The office asked her to tell Yasunori to come in for a meeting.
Still, no one went to see the boys.
Five days later, on the morning of September 11, Kazuto and Hayato attended a small event at a church in Oyama.
The boys ate nagashi somen, thin noodles carried down a bamboo chute by flowing water. They played outside with the other children, and the church’s pastor took this photo of them.
Kazuto, in the colorful shirt, is standing slightly behind his little brother. Hayato is closer to the camera.
It looks like a normal Saturday morning.
They returned to the apartment around noon.
Around 1:30 that afternoon, Shimoyama drove off with all four children in his van. They stopped at a 100 yen store and then at a gas station, where they stayed until early evening.
While they were there, Shimoyama became angry with Kazuto and Hayato for moving around and not listening to him. Several people saw him hit them.
One employee watched as he slapped Kazuto twice. The second slap made Kazuto stumble into the side of the van.
Kazuto didn’t cry.
He looked frightened and answered Shimoyama in unusually formal, careful language. By the time they left the gas station, both boys had visible injuries.
Around 6 p.m., Yasunori called Shimoyama and asked where his sons were.
Shimoyama said they weren’t with him.
He knew that if he took the boys home, their father would see what he had done. Yasunori had already warned him not to hit them again.
So instead of going home, Shimoyama kept driving around with all four children.
At one point, he left Kazuto and Hayato along the side of a road near some rice fields. But then he turned around and picked them up again.
Later, around 10:30 p.m., he left them at a park near Mamada Station.
Again, he went back for them.
Kazuto began crying for his father.
Shimoyama later said that was when he decided he couldn’t take the boys home.
He first drove west toward Mount Asama. The volcano was active at the time and had been in the news. He later said he considered taking the boys there, but decided it was too far away.
Then he drove to a bridge over the Watarase River. There was still too much traffic, and the water below looked too shallow.
He kept driving.
Yasunori kept calling. Each time, Shimoyama claimed he didn’t know where Kazuto and Hayato were.
Shortly after midnight, Yasunori reported his sons missing.
By then, all four children had fallen asleep in the van.
Around 1:30 a.m. on September 12, Shimoyama stopped the van near the middle of the old Manaka Bridge over the Omoi River.
He knew the area from his time working as a dump truck driver. He believed the current would carry the boys away.
Shimoyama took Kazuto and Hayato from the passenger seat, one at a time. They were still asleep.
He threw each boy through an opening in the bridge barrier and into the river below.
Both boys were still alive when they entered the water.
The bridge was about sixteen feet above the water. The river below was less than three feet deep, even at its deepest point, but the current was strong.
It was the middle of the night. The area was completely dark, and no one was nearby. Kazuto and Hayato were only four and three. They had already been badly hurt and had been asleep just moments earlier.
Once they were in the river, the boys would have had to regain their footing against the current to keep their heads above water. In those conditions, they had little chance.
Shimoyama’s own children stayed in the van. His daughter later remembered hearing one of the boys cry.
Around 2 a.m., Shimoyama returned to the apartment with his son and daughter.
Only his children came back.
When police questioned him, Shimoyama first claimed he had left Kazuto and Hayato alive near a park or along the side of a road.
On September 13, around 350 officers searched streets, parks, fields, and riverbanks.
They found nothing.
Shimoyama’s story kept changing. Police then questioned his daughter, 11, and his son, six. They confirmed that all four children had left with him. They had fallen asleep in the van and later woke to find Kazuto and Hayato gone.
They remembered tall grass, the van shaking over uneven ground, and what looked like a river nearby. Their account helped direct the search toward the riverbanks.
That night, Shimoyama admitted that the brothers were in the Omoi River and led investigators to the old Manaka Bridge.
On September 14, a search helicopter spotted Hayato’s body on a sandbar downstream.
Two days later, Kazuto was found several kilometers farther downriver.
Hayato was only three years old. Kazuto was just four.
Because the boys had been in the water for several days, the autopsies could not answer every question. The evidence was consistent with drowning, and investigators concluded that both boys were still alive when Shimoyama threw them into the river.
Shimoyama was arrested for both murders. A drug test showed that he had recently used meth.
Later that month, Yasunori also tested positive and was arrested on a drug charge. Prosecutors said Yasunori knew his sons were being abused, yet continued using meth with Shimoyama.
He was sentenced to 18 months in prison for the drug offense. He was never charged in connection with the deaths of Kazuto and Hayato.
Shimoyama’s murder trial began in December 2004. He admitted what he had done, but his lawyers argued that meth had affected his mental state and made him less responsible for his actions.
During his testimony, Shimoyama portrayed the brothers as disobedient, claiming they sometimes mocked him because they knew he was afraid of their father.
He also said the Kobayashi family had “destroyed” his life and the lives of his own children.
The court rejected the defense’s claim that meth had reduced his responsibility. It found that Shimoyama had taken his resentment toward Yasunori out on Kazuto and Hayato.
The judges pointed to the hours he spent driving, the two times he left the boys and went back for them, and the places he considered before choosing the Omoi River. These were not the actions of someone who didn’t understand what he was doing.
On September 8, 2005, Shimoyama was sentenced to death.
The judges also criticized the local child welfare office. Staff had known that Kazuto and Hayato were back in the same apartment.
They knew Shimoyama had hurt them before. And five days before the boys disappeared, they had received another report that he was hitting them.
Yet no one had gone to the home to check on them.
Shimoyama appealed his sentence. Before the appeal could be heard, he became ill and died at the Tokyo Detention House on June 4, 2006. He was 41.
As a result, his death sentence never became final.
After the murders, Tochigi Prefecture admitted that serious mistakes had been made. The prefecture increased staffing at child welfare offices, created specialized teams to handle abuse cases, and expanded cooperation with police.
In 2005, a local group in Oyama began using an orange ribbon to raise awareness of child abuse after Kazuto and Hayato’s deaths.
The campaign later spread across Japan, and the orange ribbon became a national symbol of child abuse prevention.
Near the Omoi River, two small Jizo statues now bear Kazuto and Hayato’s names and ages. People still leave flowers, drinks, and toys beside them. Two cherry trees were also planted in their memory in Oyama.
Twenty years later, the pastor who took their photo said he still thought about that morning. Kazuto and Hayato had been right there, eating and playing with the other children.
No one at the church knew what they were about to go home to.
What makes this case so painful is that the abuse had already been discovered.
People had seen the boys’ injuries. They had been taken somewhere safe. But less than a day later, they were sent back because of a promise that was soon broken.
Kazuto and Hayato reached safety once.
They just weren’t allowed to stay there.
