A deputy manhandling and pummeling an inmate into submission. A sexual assault unnoticed for days on the suicide watch tier. Jailhouse brawls entering second and third rounds in the absence of supervision.

Such is the chaos gripping the city’s new $150 million jail, a corrections expert testified Monday, describing an Orleans Justice Center where violence occurs “on an incredibly frequent basis.”

“There should be a goal that this not happen at the Orleans jail,” the expert, Margo Frasier, told U.S. District Judge Lance Africk, recalling the recent rape of a suicidal inmate.

The young man was attacked by a fellow inmate, even though the young man should have been under “pretty constant supervision,” said Frasier, a former sheriff in Austin, Texas, who has been keeping tabs on inmate-on-inmate attacks at the lockup.

Frasier testified on the sixth day of a hearing in federal court that will determine whether Orleans Parish Sheriff Marlin Gusman retains control of the city’s jail or is ordered to hand over those responsibilities to an outside administrator.

The U.S. Justice Department and a group of local inmates who filed a class-action lawsuit over jail conditions have asked Africk to name an outside official, known as a receiver, to manage the lockup. The plaintiffs and the government contend the jail is dangerously understaffed and that conditions are so bad they are violating the constitutional rights of inmates.

Africk has not tipped his hand on whether he intends to appoint a receiver, but he has made clear that he is losing patience with the pace of the jail reforms. “I think everybody agrees something has to change,” he said Monday.

Over the first five days of the hearing, attorneys for the Justice Department and MacArthur Justice Center law firm questioned several experts who testified that deputies essentially have not been in control of the new jail since it opened in September.

Frasier sought to place an exclamation point on that argument Monday, offering some of the most alarming testimony to date on the sheriff’s failure to implement a series of jail reforms that Africk ordered three years ago as part of a federal consent decree.

Rather than making progress, Frasier said, the Sheriff’s Office appears to be “going backwards” in many respects. She said inmates often are left unsupervised for extended periods of time, including during one incident in which a teenage inmate, Jaquan Brown, was beaten unconscious. In that case, a deputy took a lunch break and apparently was not relieved, leaving the post unguarded for about an hour.

In fact, Frasier said, inmate-on-inmate attacks at the jail have been vastly underreported, disguising the extent of the disarray.

Blake Arcuri, a Sheriff’s Office attorney, disputed that claim on cross-examination, insisting the underreporting is “not as gross as it may seem.”

But Frasier said deputies are inattentive and sloppy in their reporting of significant incidents.

Earlier this year, a deputy picked up an inmate by his throat, lifted him more than a foot in the air, “body-slammed” him to the ground and then punched him “numerous times,” Frasier said. The deputy eventually was terminated, even though his supervisor initially signed off on a report claiming the use of force had been justified.

The deputy involved in the incident was not named in open court, but a Sheriff’s Office spokeswoman later identified him as Willie Harris.

“It’s clear the supervisors don’t know what they’re doing,” Frasier said. “The result is that inmates continue to be subjected to excessive and unnecessary force, and nobody is being held … accountable.”

She also described a harrowing sexual assault this year involving an inmate who had been placed on suicide watch. The young man had been placed in a cell with an inmate who had a history of violence, Frasier said, and deputies failed to notice the rape occurred.

It wasn’t until the inmate reported the sexual assault to his mother and attorney days later that the Sheriff’s Office began a criminal investigation.

“They’re supposed to be checked much more frequently,” Frasier said, referring to inmates on suicide watch. “They were on that status, yet this occurred.”

Arcuri said the authorities intend to prosecute the inmate who committed the rape.

Frasier’s testimony marked the end of the plaintiffs’ and government’s case for receivership, an exceedingly rare legal maneuver that would strip Gusman of his core responsibility of running the jail. The sheriff has vehemently opposed the move, insisting his agency is moving in the right direction, despite a lack of adequate funding from Mayor Mitch Landrieu’s administration.

Frasier spoke at length about Gusman’s failure to establish policies for use of force, a shortcoming she said could not be attributed solely to a lack of funding. “I think part of the problem is that there is a total lack of understanding as to what this consent (decree) requires,” she said.

Gusman’s attorneys intend to call more than a dozen witnesses to make the case that control of the jail should remain in the hands of the elected sheriff. Gusman, who is expected to testify later this week, has described the push to sideline him as “an attempted coup” and de facto disenfranchisement of the voters who elected him.

The sheriff’s first witness, Carmen DeSadier, the chief of corrections at the Sheriff’s Office, acknowledged Monday that the opening of the new jail last year was rocky, to say the least. A number of deputies quit after the building opened, she said, in part, because they were unaccustomed to its “direct supervision” model in which deputies are stationed inside the tiers with the inmates.

“Staff and inmates were introduced to a new culture for the first time,” DeSadier said.

She said the Sheriff’s Office has made “major changes” in its organizational structure in recent weeks — a shift that persuaded her to return to the agency after leaving amid an internal power struggle. “It’s a step forward,” she said.

Follow Jim Mustian on Twitter, @JimMustian.