Police spent Tuesday trying to explain the heartbreaking scene discovered a day earlier at the home of 54-year-old Sandy Ford and her son Andy in a quiet Toledo neighborhood.

Firefighter’s using a sledgehammer broke down the garage door to find the bodies of 5-year-old Madalyn Hayes, her 6-year-old brother Logan and 10-year-old sister Paige slumped inside a 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.

Police said letters inside the house indicated the woman and her son plotted the murder-suicide, beginning by picking up the children from school Monday morning after their mother had dropped them off earlier.

They also had disabled the garage door opener and nailed plywood over the windows, said Toledo police Sgt. Joe Heffernan. He wouldn’t say what was in the letters, but it appeared some were written by the children.

“We’re trying to figure out all the why’s in this,” 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. Despite the grisly scene, investigators found no signs the children were forced into the car and believe all five died of carbon monoxide poisoning.

Until last week, the children had spent the last three years living with their grandparents, Sandy and Randy Ford, and their uncle at the house in a residential neighborhood close to the Michigan state line.

Their mother, Mandy Hayes, had asked her mom for help caring for the three children because a fourth child at the home was becoming disruptive, said children’s services representatives and a family friend.

“She was just being protective,” said the friend, Cammie Turner.

While the children were living with their grandparents, their parents saw them almost every day and went on outings to parks and the zoo, Turner said.

“Their kids mean everything to them,” she said.

But recently Hayes had decided they should all return home, and the children moved back in with their parents last week, upsetting Hayes’ mother, Turner said.

“Mandy wasn’t taking the kids away from her entirely,” she said. “She wanted them home. It wasn’t like she was taking them and grandma could never see them again.”

Turner said Hayes had confided that her mother was controlling, but she never seemed alarmed by it.

“It doesn’t make sense,” she said. “I can’t imagine. To have your mom …”

Police were at the house last week and children services workers met with both sides of the family, most recently on Saturday, said Dean Sparks, executive director of Lucas County Children Services.

“We only know that there were a lot of allegations back and forth,” he said, adding that Sandy Ford was worried about placing her grandchildren back in the home with their 9-year-old brother, who had been disruptive in the past.

But the agency had no authority to decide who should keep the children, Sparks said, and the parents had every right to bring them back into their home.

Turner said she never saw any indication of a strained relationship between Hayes and her mother, and they never went to court over the issue of custody.

Family members declined to comment.

Doug Hall, a neighbor who lives across the street, said he often saw the children with their uncle, raking leaves or shoveling snow. He said the only unusual thing he noticed was a police car at the house last Thursday. He said he didn’t know why it was there.

Neighbors said the family spent a lot of time together and that the Fords had put in a swimming pool this summer for the children.

Another neighbor said he saw the kids playing in the leaves just a few days ago.

“One minute they’re doing the leaves, and then the next there are cop cars all over,” Eric Pieper said.