Prison officials believe they have contained the COVID-19 outbreak at the Minnesota Correctional Facility in Moose Lake.

As of June 3, there was only one inmate remaining on isolation status at the prison, which in late March was the first in the state to record a positive test, according to a memorandum filed Friday in State District Court.

"Even though MCF-Moose Lake has almost eliminated offenders on isolation status, it nevertheless continues to make preparations to ensure it does not reach capacity in the event of an unanticipated surge of COVID-19 infection," attorneys wrote in the filing.

The Department of Corrections outlined its handling of the pandemic in a 37-page response to a petition filed in April by three Moose Lake inmates, who are seeking early release options for offenders meeting certain criteria because they allege the agency is failing to keep them safe.

According to the DOC, 79 offenders who tested positive or were presumed to have contracted the disease have since recovered. At the time of the filing, only one remained in a "step-down" environment awaiting a return to his normal unit.

But Dan Shulman, an attorney representing the inmates, said he believes those numbers significantly understate the spread of the virus within prison walls. He commended the agency for taking steps to address the pandemic, but questioned whether measures are being effectively implemented.

"They've obviously done a lot," Shulman said of the DOC, "but it would be really great if they were actually doing everything they say they're doing."

The DOC response asserts that all inmates have been provided with cloth masks, which they are expected to wear in the presence of others. Masks and social distancing rules are enforced, the memo states, but inmates have largely complied voluntarily.

Any inmates who are exhibiting symptoms are immediately moved to an isolation unit, where they receive medical care and have their own toilet and sink, the response states. Inmates are also expected to clean cells regularly.

The response notes that the DOC has expanded its work- and medical-release programs, but the agency has limited authority to let people out early from court-imposed sentences. The prison had 969 inmates Wednesday, down from about 1,050 when the outbreak started.

The memorandum credits prison officials for achieving what "appeared to be an insurmountable task" in containing the spread and limiting it to approximately 80 inmates.

"The exhaustive efforts outlined above are not only reasonable," the document states, "but they were completely effective in mitigating the spread of this unprecedented disease."

Testing protocols debated

Shulman, however, said he's still receiving reports from inmates that masks and distancing rules aren't being strictly enforced and that the outbreak has impacted far more people than officially reported.

He said he would be surprised if the true number of infected inmates wasn't in the range of 350-400.

"They're not testing people," Shulman said late Tuesday. "You look at the testing record — it's very curious in a prison that generally has 1,000 inmates that they've run, since March, 160 tests."

Shulman, a staff attorney at the American Civil Liberties Union of Minnesota, said it's possible the virus may have "run its course" and tapered off for the time being, but the threat of another outbreak lingers as long as there isn't a vaccine available.

The DOC has started mass testing for active coronavirus cases at some of its facilities. The agency reported that all 1,408 inmates tested at the Stillwater prison May 22 were negative, and that no cases were found among 386 staff and 1,102 inmates tested at Lino Lakes on June 2.

DOC spokesman Nick Kimball said the agency is "working to expand to others," but there were no firm plans for a mass test in Moose Lake, adding that testing is just one component of a multifaceted response.

Shulman argued that the agency should expand to antibody testing, which he said would give a better sense of the scale of the spread and more definitively determine which inmates have been infected and since recovered.

"If their failure to test has resulted in hundreds of people getting the disease and recovering, when they test now that's not especially useful," he said.

Kimball said antibody testing has not been recommended by the Minnesota Department of Health or the Centers for Disease Control and Prevention "due to uncertainty about accuracy and uncertainty about the significance of a positive antibody test result."

The petition for release was filed in April by the ACLU and state public defender's office on behalf of three inmates and all others who meet certain criteria — particularly those who are older and/or have existing health issues, as well as those with less than six months left to serve, are not considered a danger to the public and have a safe place to isolate in the community.

Sixth Judicial District Judge Leslie Beiers subsequently determined that the inmates had provided sufficient evidence to move forward with their claims that the DOC was failing to meet it obligation to keep inmates safe, ordering the agency to show cause for why remedies should not be ordered.

Beiers is scheduled to hear oral arguments June 23. The state has asked the judge to dismiss the action, but Shulman said he hopes to proceed to an evidentiary hearing in early August.