April Balascio lives "with the guilt of not turning my dad in sooner or trying to report him"

Growing up, April Balascio says she always had suspicions about her dad, handyman Edward Wayne Edwards. He was obsessed with murder and detective stories and loved to ingratiate himself with the cops, inserting himself into local investigations wherever they lived.

Stranger still, Edwards would often move his family in the middle of the night without warning — Balascio’s first clue that something wasn’t quite right.

“Kids aren’t stupid,” she tells PEOPLE.

But it wasn’t until 2009, as a 48-year-old mom of three grown children, that Balascio decided to look deeper, sure that she had to act on her nagging concerns.

After searching online for “cold cases” and towns that they’d lived in when she was a child to see if anything stood out, one did: the story of two teens in Watertown, Wisconsin, who had disappeared after a wedding reception in 1980, only to turn up stabbed and strangled three months later.

Balascio knew her dad had worked at that same venue and she remembered their family fleeing Watertown two days after the teens vanished. She decided to call the detective on the case, which had recently been reopened, to see if maybe her dad could have had something to do with it.

What happened next will be featured on Monday night’s episode of People Magazine Investigates, on Investigation Discovery, and is exclusively previewed above.

• For more on Edward Edwards’ dark secrets and his daughter’s search for the truth, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.

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April Balascio
| Credit: Eric Ogden

Three weeks after Balascio’s call, authorities let her know they’d obtained DNA from her dad — and it was a match to the “Sweetheart Murders” of Kelly Drew and Tim Hack, both 19, in Watertown.

“I started hyperventilating,” she says. “Because that was the moment it really hit me that my dad was the horrible, horrible person that I’d always suspected him of. I just never had the proof.”

But there was no relief. Only crippling shame, grief — and guilt.

“I didn’t want anyone to know,” Balascio says. “I had guilt by association. I thought people would think, ‘Like father, like daughter.’ ”

• Watch the premiere of People Magazine Investigates: My Father, The Serial Killer on Monday, Jan. 15, at 8 p.m. ET on Investigation Discovery.

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Edward Edwards (top right) with his wife (top left) and three of his children, including April at 3 years old (bottom left)
| Credit: Courtesy April Balascio
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Judith Straub
| Credit: Beacon Journal/Ohio.com
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William Lavaco
| Credit: Beacon Journal/Ohio.com

Once Edwards was in custody, he admitted to the murders — and more. He said he’d also been responsible for the 1977 slaying of another young couple in Ohio, Judith Straub and William Lavaco, 18 and 21, who had been killed with a shotgun with no apparent motive.

And in 1996, Edwards said, he killed his own son, “Dannie Boy” Edwards, for an insurance payout.

Though the murders may have gone unsolved if Balascio had never had the courage to investigate, she says she nonetheless lives “with the guilt of not turning my dad in sooner or trying to report him.”

“Then I live with the guilt that I turned my father in,” she says. “[Both feelings are] incredibly strong.”