One by one, a dozen Spring Creek inmates were strip-searched, then walked handcuffed and naked to empty cells where they were held for up to 12 hours with no clothing, blanket or mattress, a just-completed state investigation found. Inmates said they were led on "dog leashes" – referring to a restraint device that clips to shackles, according to the Alaska state ombudsman.

The incident at maximum-security Spring Creek Correctional Center in Seward is just now coming to light but happened in August 2013 — 10 days after a disturbance that wrecked a housing unit.

The case involved "very shocking allegations that unfortunately turned out to be true," said Kate Burkhart, state ombudsman.

The case, documented in a report posted online Wednesday, required an extensive investigation to sort out contradictory information and to interview key witnesses under oath, Burkhart said.

Of the four allegations related to an inmate's complaint, all were found "justified," the ombudsman concluded.

"Spring Creek Correctional Center staff stripped several inmates of their clothing, attached them to a 'dog leash' and walked them through House 1 naked in front of female staff," the report said, describing an allegation that contended those actions were unreasonable. "Staff placed the inmates in different cells without clothing, covering, or a mattress for several hours."

The state ombudsman's office is a legislative agency that investigates complaints against state government, and recommends ways to make it more efficient and effective.

What happened at Spring Creek violated state law, the U.S. Constitution and the Department of Corrections' own rules and policies, the investigation found.

The Department of Corrections did not dispute the findings, the report said.

The prison system is addressing the issues raised and has already implemented some of the recommendations, the corrections department said in an emailed response to questions Thursday.

Its professional conduct unit "has begun a thorough investigation into the allegations presented in the Ombudsman's report," the department said.

The chain of events began Aug. 5, 2013. Late that night, a disturbance erupted involving 14 inmates. Inmates broke porcelain toilets and sinks and flooded their cells. The incident ended the next morning. The inmates were placed in segregation cells in another housing unit of Spring Creek.

Then on Aug. 16, another inmate in that housing unit broke off a shower head and flooded the area. Prison staff members documented that other inmates were yelling and screaming support for the inmate to destroy state property. He was pepper-sprayed, subdued and searched for contraband. He was given underwear, moved to a different part of the prison, and disciplined with 40 days in solitary confinement.

Then officers went for the rest of the inmates, taking them out of cells one by one, strip-searching them and attaching them to a restraint that inmates call a dog leash while they were walked to bare, separate cells. They were kept naked for up to 12 hours, the ombudsman found.

A week later, one of the inmates filed a grievance saying he had been subjected to "sexual embarrassment or sexual harassment by several officers." He said he was put in a cold cell with blood and debris all over – the latter details were not proven out, Burkhart said.

A prison lieutenant investigated. The officer's report said the inmate had been part of a group demonstration and was restrained and uncovered for the time necessary for a search and an exam by nursing staff. The prison also needed to address a security threat "posed by misuse of state clothing," the lieutenant's report said.

Others made similar complaints and the DOC responded that they needed to be moved after a disturbance. The female staff member was a nurse on hand to treat any injuries, DOC said in its response at the time.

The inmates received blue safety smocks – a sleeveless garment sometimes issued to those under suicide watch – and later received regular prison clothing, the lieutenant contended. The prison's actions were justified, he found.

An assistant prison superintendent and later the deputy director of institutions backed the lieutenant and denied the grievances.

But besides the one inmate who wrecked the showerhead, none were disciplined for any behavior on Aug. 16, the ombudsman found.

And there's no evidence the inmates were given smocks or any other clothing for many hours, the ombudsman found.

Two sergeants and two correctional officers indicated to the ombudsman's office that the lieutenant instructed the inmates to be removed from their cells, strip-searched and left in new cells naked with "absolutely nothing" until the next day. The lieutenant disputed that.

The treatment appeared to be punishment for what happened 10 days earlier, according to the ombudsman. In that incident, the inmates used their clothing to yank bathroom fixtures from the wall, the ombudsman was told.

Strip searches are justified for the safety of staff and inmates, but once complete, DOC policy requires staff to give inmates their clothes back, the new report said.

The department also was wrong to allow the same lieutenant who was the subject of the grievance to investigate it, the report said. An objective staff member should have done so.

The ombudsman recommended that the department review its procedures concerning restraints and strip searches.

When inmates are being moved while in restraints, they should be clothed or covered for privacy, the report said.

The department changed its policy in December 2016 to require that staff members of the same sex — and out of other inmates' view — conduct strip searches. But the department also removed a requirement that strip searches are done "in a manner least offensive to the prisoner's dignity and in private, where possible." That deleted wording was vague, the department told the ombudsman.

The ombudsman also urged that correctional officers wear body cams, which would provide a record of encounters that could protect them from unjust grievances. The department said it has cameras but is still working on a policy for using them.

As to why the investigation took so long, part of the answer relates to the complexity of the case, Burkhart said.