A grand jury has indicted an Orleans Parish Sheriff’s Office deputy in connection with a gang-related stabbing three months ago at the violence-plagued Orleans Parish Prison.

The deputy, John Dupart, 42, was charged with malfeasance in office and being a principal to aggravated battery, according to court records.

The grand jury Wednesday also charged six inmates in the attack on 37-year-old Terrance Lee, an inmate stabbed more than a dozen times inside the Old Parish Prison, a building that houses many of the jail’s most violent criminal defendants. Two other inmates were charged with obstruction of justice in the case.

Few details of the stabbing were available late Thursday, and it was unclear how badly Lee was injured, but the jailhouse attack appeared to involve several reputed members of the 3NG gang, a bloody Central City operation.

The Sheriff’s Office, in a statement, said Dupart failed to follow unspecified procedures, which “resulted in an altercation” at the jail in mid-September.

“All I know is they’re saying that he allowed this to happen,” said Dupart’s defense attorney, Jeffrey Smith.

“The allegation is that he didn’t stop a fight,” Smith added, noting that Dupart is accused of being a principal to an aggravated battery — not of committing any violence. “He’s not part of any gang or anything like that, not gang-affiliated in any way, shape or form.”

Dupart had been reassigned from his post at the prison before his indictment, according to the Sheriff’s Office, and most recently was providing security at the Criminal District Courthouse. In fact, he was working there the day he was indicted, according to a courthouse source.

Dupart now has been suspended from the Sheriff’s Office, pending the outcome of the criminal proceedings.

He remained in custody late Thursday in lieu of $750,000 bail, an amount Smith called excessive. “Those bonds are higher than bonds for second-degree murder,” said Smith, who asked Judge Keva Landrum-Johnson for a hearing, set for Tuesday, on reducing it.

Dupart lives in St. Bernard Parish and has no criminal record, Smith said, adding that he has worked for the Sheriff’s Office for more than five years.

The stabbing underscored the recurring struggle OPP has had with inmates obtaining knives and other contraband. In October, Deputy Evelyn Tureaud resigned from the Sheriff’s Office after being accused of smuggling packages of contraband into the jail. Court documents show Tureaud, 22, pleaded guilty to malfeasance in office Wednesday.

Sheriff Marlin Gusman, who often is criticized for the relentless violence at OPP, issued a statement Thursday insisting his agency remains “committed to keeping everyone in our facilities safe.” The Sheriff’s Office, he noted, “initiated and managed” the investigation into Dupart.

“If anyone — including deputies — compromises that safety, we will take all necessary corrective actions,” Gusman said.

However, the stabbing highlighted the incessant jailhouse attacks OPP has seen for years and that have continued in recent months despite federal supervision and a series of court-ordered reforms known as a consent decree.

In fact, the Sheriff’s Office on Thursday also confirmed a separate attack this week that resulted in three inmates being taken to the hospital. Authorities did not release the names of those inmates but said all three had been returned to the jail within several hours.

Several of the inmates charged in Lee’s stabbing had been awaiting trial on murder charges, and the grand jury that considered the case was a special panel that is handling gang cases.

At least four of the defendants — Alfred Clay, Lonnie Ingram Jr., Darrius L. Knox and Tyrone J. Knockum — appear to be affiliated with the 3NG gang, named for the group’s stomping grounds around Third and South Galvez streets. Twenty of the gang’s alleged members were indicted in June 2013.

A 30-count state racketeering indictment accused the group of meting out deadly violence over nearly a decade to fortify its drug-dealing business in Central City. None of the 20 indicted defendants in the 3NG case has pleaded guilty or faced trial.

Knockum and another man, Terrioues “T-Red” Owney, are scheduled for trial on March 2 in that case. Those two allegedly were responsible for killing 2-year-old Keira Holmes in the courtyard of the former B.W. Cooper housing development in December 2011. Knox also was booked on a second-degree murder count in the death of Carl Anthony May, who was gunned down in February 2013 in the 2500 block of South Galvez Street.

Ingram, 32, Knox, 22, and Knockum, 24, all were charged with attempted second-degree murder in Lee’s stabbing, while Clay, 50, was charged with obstruction of justice.

Cody Williams, 25, who was charged with obstruction of justice in Lee’s attack, had been jailed on counts of second-degree murder and attempted second-degree murder in a March shooting that killed Ranalda Variste, 19, and Sandy George, 49, and injured an 18-year-old man.

Frederick Johnson, 30, who was charged with attempted second-degree murder in the stabbing, had been booked in June 2013 on second-degree murder in the shooting death of 36-year-old Ruben Brown.

Marvin Banks, 18, and Joshua Domino, 19, also were charged with attempted second-degree murder in Lee’s stabbing.

Knockum, Owney and two other men were indicted separately in August in the 2010 murders of local bounce rapper Renatta “Magnolia Shorty” Lowe and Jerome “Man-Man” Hampton as they sat in a car in New Orleans East.

Advocate staff writers John Simerman and Danny Monteverde contributed to this report.