LOS ANGELES (AP) — Juan Corona, who became the nation’s most prolific serial killer when he was convicted in 1971 of killing and burying the bodies of 25 California farm laborers, died Monday at age 85.

Corona died Monday at an undisclosed hospital, Vicky Waters of the state Department of Corrections and Rehabilitation reported. He had been serving a life sentence at a state prison in Corcoran, California, before he was hospitalized.

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juan corona cal department of corrections

Juan Corona (CDCR)

The farm laborer contractor was convicted of killing 25 farm workers, including many he’d hired, and burying their bodies in shallow graves on orchards and farms along the Feather River, north of Sacramento.

Most were stabbed and hacked to death. One was shot in the head.

Corona was arrested after a peach farmer who had contracted with him for hired pickers became suspicious upon finding a hole that had been freshly dug and then quickly filled in.

The farmer called authorities, suspicious someone was burying garbage in his orchard. Instead they found the body of a man whose head had been hacked and his torso riddled with stab wounds.

Corona was arrested a week later and subsequent searches turned up the bodies of 24 more people, including several Corona had recruited for farm work.

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He was convicted of 25 counts of murder in 1971 and sentenced to 25 concurrent life sentences.

He nearly died in a prison stabbing two years later that cost him the sight in his left eye.

Juan Corona in an earlier picture and in 2018 (CDCR)

In 1978 an appeals court overturned Corona’s conviction, ruling he had received incompetent representation from his attorney.

He remained incarcerated while he was retried and was convicted again in 1982 on the same 25 counts.

He would be denied parole eight times, most recently in 2016.

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“It was a gruesome manner of killing. He hacked these people to death,” Sutter County District Attorney Amanda Hopper told The Associated Press after attending Corona’s last parole hearing.