An ailing great-grandmother says she’s desperately in need of a kidney transplant — because she’s determined to outlive the pedophile who killed her daughter in Michigan 52 years ago, according to a new report.

Edith Siordia, 79, who now lives in California, says her daughter Sonya was 7 years old in 1967 when she walked back from Stocking Elementary School in Grand Rapids to pick up a book she forgot, .

Instead of grabbing the book and returning to school, the girl was kidnapped, raped and killed. Her body was discovered by horseback riders, according to the report.

Now, Siordia — who is battling life-threatening kidney disease and made the first visit to her daughter’s grave in 25 years — told the paper that she wants more than anything to outlive the killer, Theodore Glenn Williams, now 80, and continue to be her daughter’s voice.

Williams was a house painter who dated Siordia’s babysitter, the paper reported.

He is being held at a psychiatric hospital under a criminal sexual psychopath law repealed in 1969 — and is believed to be the only person still held under the law, according to the report.

He’s asked that a federal judge order his release and provide millions of dollars in restitution for his life in the facility, according to the report.

But Siordia won’t have it.

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“If I have to fight this again, I’m going to do it ‘til my last breath, if I can, you know?” she told the paper.

She’s consistently battled Williams’ requests for release from state hospitals, in addition to weekend furloughs — and was shocked to learn that he’d been collecting Social Security benefits in the hospital.

Charges have been dismissed against Williams in another child rape and murder case — involving victim Laura Jo Sutliffe, according to the report. When authorities found Sonya’s body, Williams reportedly also led them to Laura’s.

Siordia called Williams calculating and manipulative, and recalled some disturbing moments when her daughter first went missing.

“He would sit in my kitchen and say, ‘If I could get my hands on the SOB, I’d kill him,’” she told the outlet. “All that time it was him.”

Now Siordia goes for dialysis three times each week and desperately needs a kidney from a live donor, according to the report.

“I’ve gotta stay alive for Sonya, you know, and for my other kids, too,” she said.

When asked if she’d accept a kidney from Williams, she struggled to respond.

“I can’t answer that,” she told the paper. “I don’t think I would take it. I hope somebody donates me a kidney, but I don’t want it to be him.”