(CBS/AP) TOLEDO, Ohio - An Ohio mother said Wednesday that her mother and brother weren't in their "right minds" when they allegedly killed her three children this week in what police believe was a murder-suicide.
Police said notes found at a Toledo house indicated that the grandmother and uncle of 5-year-old Madalyn, 7-year-old Logan and 10-year-old Paige Hayes planned to kill themselves and the children by funneling fumes from a pickup truck into a car where their five bodies were found Monday.
The children, their 54-year-old grandmother Sandy Ford, and their 32-year-old uncle Andy Ford, died of carbon monoxide poisoning, a coroner ruled Wednesday.
Mandy Hayes, the children's mother, told CBS affliate WTOL in Toledo that her mom was her best friend and she was close to her brother.
"I don't know what happened," Hayes said. "They weren't in their right minds. That's all I can say. Something snapped, where it just - I don't know. I can't explain it, really."
Hayes' husband, Chris, drew a different conclusion.
"I think she really did not want those kids to ever come home, is what the deal was there," he said of the grandmother in the WTOL interview. "She felt that she was their mother."
Investigators and family friends said the murder-suicide appears to stem from a family disagreement over where the children should live.
The children lived with their grandmother for the past three years when Mandy Hayes asked her mother to care for them after another son at home had behavior problems and was becoming disruptive, according to children services workers. Sandy Ford was angry when the children moved back into their parents' home within the past week, believing the youngsters would be better off with her.
Police were called to intervene twice last week, but they said they saw no signs the children were in danger.
Ford picked up the children from school Monday morning not long after their mother dropped them off, and the grandmother took them back to her home, police said.
Hayes said when the school called to tell her the kids were not there, she called police.
"I figured it was my mom that had snatched them," she said. She kept calling her mom but she never answered.
Chris Hayes said he also knew the grandmother was involved once he learned the children were not at the school.
"I told my wife to keep calling the police, telling them - look, find out what car they're in, if they're going anywhere - get an Amber Alert, something," he said.
Authorities were called to the home by the children's frantic grandfather after he discovered the letters and was unable to force open the garage door.
Firefighters used a sledgehammer to break down the garage door and found the children's bodies slumped inside the car along with their grandmother and uncle. Two hoses attached to the exhaust of a pickup truck pumped gas fumes through the car's rear window.
A funeral for the children is set for Monday in Toledo with visitation scheduled for this weekend.