On March 25, 1988, Jacque MacDonald got the phone call that changed her life: Her 32-year-old daughter, Debi Whitlock, had been found with her throat slashed in her Modesto, Calif. home.
Debi’s husband, who was returning home from a bachelor party when he discovered his wife’s body, was not home during the killing. But the couple’s 3-year-old daughter was, and the little girl slept through the attack.
Nothing would ever be the same for MacDonald: “When Debi died, the life went out of me,” she told PEOPLE in 1997.
The murder set her on a mission: From that point forward, she was resolved to find her daughter’s killer. Her efforts are chronicled in the upcoming episode of People Magazine Investigates. Titled Nine Years in the Shadows, the episode airs tonight at 10 ET on Investigation Discovery. (An exclusive clip is shown above.)
As soon as MacDonald got home from Debi’s funeral, she called the TV show Unsolved Mysteries, which did a segment on the killing. America’s Most Wanted also featured Debi’s case thanks to MacDonald’s efforts.
Soon after Debi’s death, MacDonald moved from Minnesota to California to be closer to the investigation.
“I think of my life in two segments,” she told the Modesto Bee in 2008. “The happy one and the one after.”
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MacDonald also founded a support group for relatives of murder victims and rented billboards featuring her daughter’s picture and offering a $10,000 reward for information. She also convinced local pizza shops to distribute flyers on her daughter’s case, and even got space on grocery carts.
“It was love that drove me,” she told PEOPLE. “I had to do it for Debi. She didn’t deserve this.”
The killer was arrested in 1997 — and his identity shocked those who had been following the case.
Five days after the arrest, MacDonald went to Debi’s grave. She told PEOPLE that she touched her daughter’s headstone and said, “We did it, kid.”
She added, “You can rest in peace.”
People Magazine Investigates: Nine Years in the Shadows airs tonight at 10 ET on Investigation Discovery.