MADISON, Wis. (AP) — Two of the four inmates found dead at Waupun Correctional Institution since June died of a drug overdose and a stroke, a medical examiner said Wednesday.

Tyshun Lemons, 30, was found dead at the prison on Oct. 2. Cameron Williams, 24, was found dead there on Oct. 30.

Dodge County Medical Examiner PJ Schoebel said in a telephone interview that Lemons overdosed on acetyl fentanyl, a potent opioid painkiller. He has ruled Lemons’ death accidental.

Lemons was sentenced in 2015 to 13 years in prison after he was convicted of being a party to armed robbery and reckless endangerment, according to court records.

As for Williams, a blood vessel in his brain burst, resulting in a fatal stroke, Schoebel said. He has ruled that death as natural.

Williams had bounced around the corrections system since he was convicted in 2019 of theft and bail jumping, Department of Corrections records show.

Dean Hoffmann killed himself in solitary confinement at Waupun in June. Donald Maier was found dead at the facility on Feb. 22. Authorities haven’t released any details in either of those deaths. Schoebel said he had nothing to report on those deaths.

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Dodge County Sheriff Dale Schmidt said in telephone interviews that those deaths remain under investigation. He declined to comment on how Lemons obtained the fentanyl. Department of Corrections officials also didn’t immediately respond to an email inquiring about how Lemons obtained the drug.

The Department of Corrections instituted lockdowns at Waupun as well as at prisons in Green Bay and Stanley last year due to a shortage of guards.

A group of Waupun inmates filed a federal lawsuit in October saying lockdown conditions at the facility amount to cruel and unusual punishment. And last month Hoffmann’s daughter filed a federal lawsuit alleging Waupun officials failed to provide her father with adequate mental health care and medications. Those cases are pending.

Stanley resumed normal operations in late November. Movement restrictions have eased at Waupun and Green Bay, but some still remain in place.

shedding more light on how two Wisconsin prison inmates died last year. Thirty-year-old Tyshun Lemons was found dead at Waupun Correctional Institution on Oct. 2. Twenty-four-year-old Cameron Williams was found dead at the facility on Oct. 30. Dodge County Medical Examiner PJ Schoebel said in a telephone interview Wednesday that Lemons overdosed on acetyl fentanyl, a potent opioid painkiller. Williams died of a stroke that occurred naturally. Schoebel declined further comment. Lemons and Williams were among four Waupun inmates who have died since June 2023. Dean Hoffman killed himself in solitary confinement in June and Donald Maier died at the facility last month.