(CNN) For three decades, the abduction, rape and murder of 8-year-old April Tinsley in April 1988 had frustrated Indiana investigators.

The mysterious killer's taunting messages admitting to the crime, scrawled on a barn door and on paper notes threatening to kill again, only added to the desire to solve the cold case. Still, no suspect could be found.

But thanks to advances in genealogy and DNA technology, the suspected killer was arrested and then confessed to the crime on Sunday -- more than 30 years after April's death.

John D. Miller, 59, was preliminarily charged with murder, child molesting and criminal confinement of a victim under 14, according to Allen County Court's website.

"Right now I'm numb," the girl's mother, Janet Tinsley, said Tuesday on CNN sister network HLN.

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