New Orleans has an understaffed and dysfunctional jail that “nobody knows how to run,” a national corrections expert testified Wednesday, bemoaning the lack of progress at the lockup despite three years of federal supervision and the opening last year of a new $150 million housing facility.

The expert, Susan McCampbell, told U.S. District Judge Lance Africk that Orleans Parish Sheriff Marlin Gusman appears to have the desire — but not the know-how — to improve conditions that the federal government says are unconstitutional. The sheriff still has no plan to address violence at the Orleans Justice Center, she said.

“They just have no clue, and I think that’s what’s been frustrating to us,” McCampbell said before a packed courtroom, referring to the sheriff and much of his top staff. “I don’t think the sheriff lacks the will to do it. What they lack is knowledge about how to run a jail system.”

McCampbell testified most of the day Wednesday as the first witness in an extraordinary hearing that will determine whether Gusman retains control of day-to-day operations at the jail. The U.S. Justice Department asked Africk last month to appoint an outside administrator, known as a receiver, to supplant Gusman, arguing the third-term sheriff has failed to carry out a series of reforms ordered in 2013.

The reforms, outlined in a class-action settlement known as consent decree, remain largely unfulfilled. McCampbell and her team have warned that the Sheriff’s Office has taken a number of steps in the wrong direction over the past six months. Inmate-on-inmate attacks are occurring on a regular basis, she said, but are being underreported by Sheriff’s Office brass.

“Right now, there’s not a shared common knowledge base in the Orleans Parish Sheriff’s Office,” she said. “There continues to be way too much violence in the jail.”

The appointment of a receiver would strip Gusman of his core responsibilities, but the maneuver would not remove him from office. The sheriff is expected to testify during the hearing, which may not end until Friday afternoon.

Even though hundreds of New Orleans inmates have been moved out of the jail in recent months, McCampbell testified that there still aren’t enough deputies available to respond to emergencies. Guards should be interacting with inmates and attempting to head off problems but instead seem to be “cemented” to their chairs, she said.

As recently as this week, McCampbell said she encountered unsupervised inmates during a tour of the jail. One man, bleeding from a recent surgery, banged on a door repeatedly, his cries for medical attention falling on deaf ears.

“I don’t want to be melodramatic, but we are dealing with people’s lives here,” McCampbell said. The cultural change needed within the Sheriff’s Office hasn’t even begun yet, she added. “Right now,” McCampbell said, “I don’t see us moving past where we are” under the current leadership.

Africk, who has presided over the jail litigation for four years, has been reluctant to micromanage Gusman or intervene in the sheriff’s funding battle with Mayor Mitch Landrieu’s administration. But he made clear Wednesday that he is entertaining the government’s request that he sideline Gusman.

“I ’m not waiting around another five years” for change, the judge told one of the sheriff’s attorneys during one spirited exchange.

Gusman has blamed the jail’s problems on the Landrieu administration, claiming city leaders have flouted state law by failing to adequately fund the Sheriff’s Office. He has referred to the Justice Department’s push for receivership as an attempted “coup” that would usurp the will of local voters who overwhelmingly re-elected him in 2014.

McCampbell recounted her frustrations in dealing with the Sheriff’s Office, saying the agency lacked even a “baseline” understanding of how to operate a jail when she was appointed to monitor the reforms. Gusman, a former chief administrative officer at City Hall, had no prior law enforcement experience when he took office in 2004.

“We had to basically start at the beginning in terms of what’s accepted correctional practice,” McCampbell said.

McCampbell cited a host of red flags, including the regular underreporting of uses of force by deputies. “It goes to the basic, fundamental integrity of the agency if there’s underreporting,” she said.

The Sheriff’s Office was slow to develop a transition team when it moved into the new jail last year and closed the notoriously violent Orleans Parish Prison, she said. The agency essentially is redoing that process now, she said, as understaffing and inadequate training recently prompted the transfer of hundreds of pretrial inmates to jails in other parishes.

“It’s a downward spiral when you don’t start out with adequate policies and procedures,” McCampbell said. “This is building a jail from the ground up.”

McCampbell appears to have become estranged from the Sheriff’s Office in recent weeks, and her testimony Wednesday made clear that she has lost faith in the sheriff to turn things around. She said she learned only on Monday that the Sheriff’s Office had transferred a number of inmates to Madison and Avoyelles parishes without her knowledge.

That’s troubling, she suggested, because the consent decree protects New Orleans inmates regardless of where they are being held. Unlike some of the other facilities around the state housing New Orleans inmates, McCampbell said she did not have the opportunity to inspect the lockups in Madison and Avoyelles parishes to ensure the living conditions were acceptable before the transfers.

James Williams, an attorney for Gusman, grilled McCampbell on cross-examination, challenging her independence and credibility. He even suggested that she was in cahoots with the Justice Department.

Williams maintained the sheriff has made progress that was temporarily stunted by the opening in September of the Orleans Justice Center. McCampbell acknowledged under questioning that it takes time for deputies to adjust to a new jail, particularly one in which guards are expected to “directly supervise” the inmates.

The hearing will continue Thursday morning with testimony from Dr. Raymond F. Patters, a mental health experts who has voiced concerns about the treatment of mentally ill inmates in New Orleans.

Follow Jim Mustian on Twitter, @JimMustian .