(CNN) -- An Ohio man stabbed his ex-wife to death outside his apartment, then had his 13-year-old son call police before calmly getting on the phone himself.
"My dad just killed my mom. He just told me to call you guys," the son said, based on a recording of the 911 call released by the Grove City Police Department. "He just ran outside and killed my mom. And she's laying in the grass in front of the apartment."
Jeremy Roberts, 38, is in custody and will be charged with murder in connection with his ex-wife Candice Roberts' death, police said.
The victim had gone to the suspect's apartment in Grove City, about 10 miles southwest of Columbus, before 9 a.m. Sunday morning to pick up their two children, police said.
Sometime thereafter, the 13-year-old boy phoned police to tell them his mother was dead and his father was responsible. The child then can be overheard telling his father, "I don't want to see you right now."
Roberts himself then gets on the line, giving the apartment's address and informing police that the "only" weapon -- a knife -- was outside with his ex-wife.
"What did you do?" the dispatcher asks him.
"She's covered in a blanket. You guys will see," Roberts responds in an even-keeled voice.
He can then be heard, on the nearly five-minute 911 call, telling his children that they have a "good big sister (who) will take care of you guys."
"I told you that there's a lot of things that you don't understand, and you don't know. And now there's no choice for them to come out," Roberts said to them, as recorded in the 911 call, without detailing what he meant.
Before going to the front door -- and handing the phone back to his 13-year-old son -- Roberts says, "One more hug. I love you guys." A small child can be heard crying in the background.
Candice Roberts' 16-year-old daughter told CNN affiliate WCMH she feels "incomplete and abandoned" after the death of her mother, whom she said "was always there for me." She said her brother is haunted by what he saw.
"My brother says that every time he opens his eyes, he sees my mother's face and her yelling, 'Help me!'" the teenager said. "And she sees my dad standing there with the blood all over him, and the knife in his hand."
The daughter added that she "would do everything for him to be held accountable."
"You don't just get to murder somebody and get away with it," she said.