Chad Doerman, 32, who is also accused of wounding the boys' mother at the family’s home, has been charged with aggravated murder, authorities said.
Clermont County's chief prosecutor of Municipal Court, David Gast, said during Doerman's arraignment Friday that one of the boys tried to flee into a nearby field but Doerman "hunted" his son down and brought him back to their home before killing him.
Doerman's bail has been set at $20 million. Court records did not indicate whether he was represented by a lawyer at his arraignment. He is currently being held in Clermont County Jail.
Gast called the killings the worst crime he’d ever seen.
Deputies responded to the home in Monroe Township shortly before 4:30 p.m. Thursday after receiving a pair of 911 calls, one apparently from the mother who was screaming that "her babies had been shot" and another from a passing motorist who said a girl was running down the street saying her father was killing people, a news release from the Clermont County Sheriff’s Office said.
The deputies found three boys, ages 3, 4 and 7, outside the home with gunshot wounds and tried to save their lives, but the children died at the scene.
"They held these children knowing there was nothing they could do," Gast said. "How do you unsee that sort of abomination?"
FILE - Chad Doerman, 32, mug shot. (Clermont County Sheriff's Office)
The boys' named have not been released.
"This was the man that everyday they woke up looking to for protection, love and guidance in all things, ..." Gast said. "He was their world, he was their guardian and he executed them in cold blood."
The sheriff's office said the 34-year-old mother, who was not identified, was outside the home and had suffered a gunshot to the hand while trying to shield her sons from their father. She was transported to a hospital with injuries that did not appear to be life-threatening.
Doerman was found sitting on a stoop at the home and was taken into custody without incident. He was arraigned on three counts of aggravated murder Friday.
Officials have not released a motive behind the shootings.
Neighbors in Monroe Township, which is about 75 miles (120 kilometers) west of Columbus, reported hearing several shots fired in what they said is usually a quiet, calm neighborhood.
"I was sitting in the garage, and all of a sudden, I hear ‘boom, boom’ and like five more, and I was like, ‘That’s seven shots,’" Alexis Spoonamore told WLWT-TV in Cincinnati. "I’m shaking. It was a lot. It was bad."