Scores of protesters arrested last summer following Alton Sterling's fatal shooting were treated "like animals" and humiliated inside the East Baton Rouge Parish Prison, according to a scathing new report that describes the lockup's conditions as so bad as to be unconstitutional. 

The demonstrators, most of whom were booked on counts of obstructing a highway, were subjected to excessive force, including the indiscriminate use of pepper spray by guards, and spent hours or days locked in overcrowded cells "caked with grime and blood," according to the report, prepared by The Promise of Justice Initiative, a New Orleans-based advocacy group.

The report, to be released Monday, accuses guards of retaliating against protesters for participating in demonstrations that went on for days following the fatal shooting of Sterling in a confrontation with police outside a convenience store.

But the report alleges the mistreatment of the protesters reflects a more systemic oppression inmates endure at the jail on a daily basis. Moreover, the report claims, the East Baton Rouge Parish Sheriff's Office "appears to encourage or at least tolerate abusive and humiliating conduct of guards."

"The arrest and detention of approximately 180 individuals protesting the police killing of Alton Sterling provided a distressing window into the actual conditions of East Baton Rouge Parish Prison," the report says. "Unfortunately, this report reflects the treatment of detainees in the East Baton Rouge Parish Prison when the whole world was watching."

The jail's warden, Dennis Grimes, defended the actions of his guards as "appropriate, professional and well within constitutional standards," adding they "at all times acted appropriately." 

"The claims of the protesters are without merit," Grimes said.

The report, based on interviews with more than a dozen protesters, echos several contemporaneous accounts of the protesters' time behind bars published last summer by The Advocate and other news outlets. But it offers a more detailed window into what the report describes as the "unconstitutional hardship" the protesters endured, including the repeated denial of medical treatment inside the jail, whether for injuries sustained during arrest or some other pre-existing condition.

"How we treat the people we incarcerate defines us, and when we take people who are protesting racism and violence and treat them with brute force, it divides our communities, undermines our confidence in the justice system and demeans all of us," said G. Ben Cohen, an attorney with The Promise of Justice Initiative. "We owe folks a better system."

Thousands of protesters descended on the Capital City following Sterling's death, clashing with police in a series of run-ins along Airline Highway and Goodwood Avenue — near the Baton Rouge Police Department headquarters — and a march on Government Street that culminated in another confrontation. Hundreds of police officers, some donning riot gear, drew a hard line in their efforts to maintain traffic on the city's critical thoroughfares.

Many of those arrested were accused of illegally stepping into the roadway, a misdemeanor count that, in many cases, prosecutors quickly declined to pursue. At least three journalists were taken into custody, as was a prominent Black Lives Matters activist, DeRay Mckesson. 

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The arrests prompted a series of civil-rights lawsuits, including a class-action complaint that recently resulted in a proposed settlement — pending the approval of a federal judge — in which some 80 protesters would receive cash payments between $500 and $1,000 and have their arrest records expunged.  

While the litigation surrounding the arrests has largely focused on the actions of the city police, the report from the Promise of Justice Initiative examined the protesters' plight after they were booked into Parish Prison. 

Erica Navalance, the report's lead author, said the "two most disturbing aspects of our investigation were that those detained for minor infractions were forced to endure threats of brutal force and humiliation, and that it might actually be worse for those regularly arrested in East Baton Rouge on minor offenses."

One of those arrested, Jenna Finkle, "spent her night in prison surrounded by strangers and guards she could not see" because the authorities would not return her eyeglasses to her. The report says she was crammed into a cell meant for 10 people that was holding between 17 and 24. "The cell was so tight that women sat on the ground right next to the toilets, which had to be used without any privacy," the report says.  

Virtually all of the protesters were denied a free phone call upon being booked, the report found, and they were deprived of drinking water and "basic supplies, including tampons, soap, running water and toothbrushes."

At least seven protesters described "large groups of inmates being pepper-sprayed for various reasons, none of which included threats to officer or prison safety, in violation of the law and established policies." 

"The chemical spray was so intense that detainees down the hall were coughing, choking and had burning eyes," the report says. "Even officers had to step outside to get fresh air because of the excessive spray."

Guards were "openly racist," the report said, and one even referred to an inmate housing unit as a "slave plantation," the report alleges. The protesters, some of whom began singing in the jail, claimed they were threatened with the loss of their court date if they did not be quiet.  

"When one woman rhetorically asked out loud, 'How many people are going to be killed before we wake up?,' an officer responded by staring at her threateningly and responding 'As many as needed,'" the report says. 

While he defended his guards, Grimes, the warden, acknowledged that the parish prison is "old and outdated."

"Efforts have been made by the city-parish for a tax to provide the parish with a new facility; however, the voters in the parish have not approved taxes for financing a new prison," he said. "Unfortunately, the parish prison is limited and it is the only facility for all arrestees within the parish regardless of the crime charged whether a misdemeanor or felony."

Follow Jim Mustian on Twitter, @JimMustian.