KALAMAZOO, Mich. (WOOD) — The paternal grandfather of missing mom Heather Kelley’s eight children has a message for the unidentified person of interest in her disappearance: Help police find her.

“If you had anything to do with it, confess, get it over with. Don’t make people suffer,” Stephen Martin Sr., of Kalamazoo, told News 8 on Tuesday.

“I just want to know if she’s alive. If she’s not, I can get on with it better, but I can’t without knowing,” he said. “I don’t believe the kids should have to suffer, them poor kids.”

Kelley, 35, who was living in Portage, disappeared on Dec. 10. She had called her kids that night, told them she’d be home soon, but never returned.

Police said they recovered her car, with evidence of foul play, the next day near North Sprinkle Road and East Michigan Avenue in Comstock Township. They wouldn’t say what that evidence was. That discovery led to searches of the area.

Martin said that Kelley and his son never married but were together 15 years or so until separating about two years ago.

He is estranged from his son, but said he believes the children are now staying with him.

In a press conference on Monday, police said they had identified a person of interest in the disappearance.

“When I say person of interest, I mean we believe that that person has some information that will help us locate our missing person,” Kalamazoo County Sheriff Richard Fuller said.

But police wouldn’t say if that person, who is locked up on a separate charge, is cooperating.

The grandfather said police have told him very little about the investigation. He fears the worst, especially after police said they’d found evidence of foul play.

“She’s gone,” the grandfather said. “I know she is. Why? She didn’t do anything to anybody. She was a good mom. She didn’t do a thing to nobody.”