Stillwater prison has been in a partial lock down in the four weeks since the killing of a corrections officer.

That has some advocates concerned about inmates being restricted to their cells — for as long as 23 hours a day — saying such long-term isolation can be detrimental to mental health.

Corrections officials have said they don't have a target date for when the lockdown will be completely lifted and normal programming resumed, saying the transition "must be done with intention, prioritizing staff and offender safety."

But on Wednesday, Teresa Nelson, legal director for the American Civil Liberties Union (ACLU) of Minnesota questioned whether officials have adequate justification for taking so long to return to the prison's normal schedule.

"What is the purpose behind it when you know the person who killed this guard acted alone," Nelson said. "The only purpose I can think of is to send a message to everybody else — 'We're not going to take anymore misconduct.' "

Nelson said the ACLU will contact the Department of Corrections and express its concerns and find out why the prison remains on lockdown.

Others also question the lengthy lockdown and are concerned about inmate reports of what they called human rights violations.

"Conditions are inhumane," said Joanna Nuñez of Twin Cities Incarcerated Workers Organizing Committee — a group of activists inside and outside prison. She said inmates reported they hadn't received more than three showers in 24 days and were locked in their cells for 20 consecutive days. The group cites complaints regarding a lack of clean clothes, stench from garbage and limited toiletries, including toilet paper.

Sarah Fitzgerald, Corrections Department spokeswoman, disputed the allegations.

Inmates were confined to their cells for four days after the corrections officer was killed, with the exception of emergency medical needs, she said. Inmates are being allowed to shower every other day, up from one shower every three days earlier in the lockdown.

"We are now on a reduced out of cell schedule that includes 1 hour recreation periods, visiting medical and mental health appointments, pick up of property and canteen (when scheduled)," she said in a written statement. A limited number of inmates involved in food preparation report to work in the kitchen, she said.

The prison is providing fresh linen during a weekly exchange and the inmates launder their own clothing, which was restricted until out-of-cell recreation time was granted, she said. Inmates must eat meals in their cells.

Garrett Fitzgerald, a legal investigator in the Twin Cities, said he's communicated with an inmate who has confirmed some of what Nuñez's group has reported. He said the inmate said he had only two showers in two weeks.

"It's not as bad as it was two weeks ago, but the key issue is how much longer before the lockdown is lifted," he said. "It's retribution and collective punishment."

Nelson said the length of time it's taken to lift the lockdown seems unusual: "We're nearing a month. That's a long time."

Reports that inmates were confined to the cells for 23 hours a day for some of that time are troubling, Nelson said. "In effect, [you're] putting these prisoners into solitary confinement. … It's counterproductive because we know solitary confinement has really harmful effects on mental health."

When courts consider litigation over prison policies or procedures, the standard is whether it's related to legitimate security concerns, Nelson said. "The courts are deferential to the prisons," she said. "But the prison has to articulate some need for a lockdown. I'm not sure what that need is here."

Joseph Gomm, 45, of Blaine, was allegedly attacked by an inmate in an industry building at the prison on July 18.