An Oak Park Heights inmate who recently tested positive for the corona­virus while undergoing cancer treatment at the University of Minnesota Medical Center died Sunday, becoming the fourth state prisoner to succumb to the virus.

Two Faribault inmates also remain hospitalized with COVID-19 complications and are on ventilators.

The 73-year-old man, who has not yet been identified by the Department of Corrections, died at the university hospital. Authorities are not sure when he contracted the virus but say he suffered from terminal kidney cancer.

In a statement, DOC Commissioner Paul Schnell expressed his sympathies to the man's family.

"Since the beginning of this pandemic we've worked to take all reasonable steps to minimize the introduction and spread of COVID-19 in the state's correctional facilities for the well-being of those we serve and our staff," he said. "Just like in our communities, this is a very difficult time for those incarcerated in our facilities, and for our staff who are working to keep them safe."

Most prisons have remained on semi-permanent lockdown since March, prohibiting outside visitors, restricting inmate movements and disrupting educational programming to fight the virus' spread.

But the outbreak still slipped behind bars last spring, hopping from prisons in Moose Lake to Faribault, St. Cloud and Stillwater, now among the largest known hot spots of infections in the state. Of the 1,255 inmates housed there, more than 927 — or roughly 75% of the overall population — have tested positive, in addition to nearly 200 staff members.

The spike in positivity rates prompted intense criticism from criminal justice advocates and relatives of the incarcerated, some of whom accused Schnell of allowing the virus to spread so prisoners would eventually achieve "herd immunity."

Schnell balked at the assertion, noting that Stillwater didn't see its first case until late September.

"It's exceedingly risky and puts people in danger," he said in an interview. "For five and a half months it wasn't our strategy and it's not our strategy now."

Schnell attributed many of the transmissions to the high number of asymptomatic staff and inmates, while tying the largest outbreak at Stillwater to the heating system, which reduced outside airflow after temperatures plummeted in October.

But the American Civil Liberties Union of Minnesota (ACLU) doesn't accept that. In its second legal challenge, the nonprofit sued the prison system last month alleging, among other things: mismanagement of the crisis, a complete lack of social distancing, refusals by staff to wear masks and unsanitary conditions. That case is pending.

Student volunteers at Mitchell Hamline School of Law helped hundreds of nonviolent and medically vulnerable inmates most endangered by the pandemic apply for conditional medical release this year, but only a small fraction were approved. Roughly 200 of at least 2,300 inmates with underlying health conditions have since been granted early release.

"When we looked at the numbers in the end, we felt like we universally failed," said Jon Geffen, who helped oversee the program and acts as director of the law school's Reentry Clinic. Some applicants were denied based on a public safety review by DOC officials, he said, but others were dismissed without a clear explanation and never given the opportunity to appeal.

"Family members of the people housed there have a right to be frustrated and concerned," Geffen said. "Their family members aren't safe."

Since March, more than 2,750 Minnesota inmates have tested positive for the respiratory disease, including 558 who are currently sick. At least 736 corrections staff members around the state have also fallen ill with COVID-19. More than half have since returned to duty.

Four male prisoners, who were serving sentences at Faribault, Stillwater and Oak Park Heights, died shortly after contracting the virus.

Each of the men reportedly had extensive medical histories and ranked among the most high risk but did not qualify or were denied early release due to the nature of their convictions.

None of Minnesota's 11 prisons is equipped with an intensive care unit, and the state agency does not own a ventilator.

As congregant living facilities, prisons should be among the first wave to get a vaccine, once it receives emergency approval from the FDA.

Corrections officials are preparing for that day by identifying inmates most susceptible to infection and plotting out a distribution plan.

"It's not going to go as fast as any of us would like," Schnell said. "But the demand is going to be huge."