At a New Orleans City Council committee hearing last week, District Attorney Leon Cannizzaro ladled warm praise on criminal defense attorney Jason Williams, saying he was delighted the recently elected at-large councilman has taken a career detour.

“We’d much rather see you sitting over there than on the opposite side of the courtroom,” Cannizzaro said. “Visit in my office, not the courthouse.”

But prosecutors with Cannizzaro’s office have called on Williams to return to the courthouse at Tulane Avenue and Broad Street on Tuesday, though for just one task: to testify in a criminal case that started Monday and could land one of his former clients behind bars for decades.

Williams is expected to testify under subpoena about text message exchanges he may have had with Keith Kisack in late 2011, while the murder defendant was behind bars. Prosecutors, who hope to convict Kisack on a contraband charge from a cellphone found in the jail, fought a legal battle to secure Williams’ appearance.

Because of his conviction record, which dates back to the early 1990s, Kisack, 39, could face 20 years or more in prison if he’s convicted and sentenced under the state’s habitual offender law.

The phone, found tucked in a black sock in a crevice in the wall of the C-2 tier of Orleans Parish Prison during a Dec. 27, 2011, shakedown, contained numerous texts from Kisack and photos that purportedly include a “selfie.”

Kisack has been locked up since 2009, awaiting murder charges and also later counts of contraband possession and resisting an officer with force.

The phone also contained several text message exchanges to and from Williams’ cellphone number.

Williams, who is not suspected of any crime, withdrew as Kisack’s attorney when the text messages came up. Some were holiday greetings exchanged in late 2011.

“Happy Thanksgiving KK ... We gonna try to make this your last one in that place,” reads one message sent Nov. 24, 2011, from the number prosecutors attribute to Williams.

“Merry X-mas 2 u and ur. Hope u enjoy. Man i am bout to lose it. KK,” reads another message sent Dec. 25, 2011, to Williams’ apparent number.

Prosecutors say Kisack goes by KK and that Williams called him that.

Because the text messages didn’t involve legal matters, prosecutors argued that they were not protected by attorney-client privilege, and higher courts agreed that prosecutors could question Williams about them.

Kisack appeared in court Monday in a white collared shirt, red knit cap and bright red tie.

Assistant District Attorney Jason Napoli told the six-member jury that the evidence against Kisack is clear.

“This case will not even be about the facts. It will not be about the law. It will be about your ability to follow the law,” Napoli said. “The evidence in this case is overwhelming.”

Orleans Parish Sheriff’s Office Cpl. Manuel Walters testified that while the phone contained pictures of multiple inmates, the only person identified as the sender or recipient of messages from the phone was “Keith or K.K.”

Defense attorneys Ike Spears and Eusi Phillips challenged the investigation into the phone, however, saying nobody bothered to see who registered it or paid the bills. Nor was anyone else found on the phone prosecuted, they argued. Spears insisted that Kisack was being singled out and prosecuted to the hilt in a knee-jerk response to the continuing problem of contraband in the jail and notorious, widely aired videos that show inmates shooting up drugs, drinking beer, unloading a handgun and gambling inside the now-shuttered House of Detention.

“You knew that your boss, (Sheriff) Marlin Gusman, was getting a lot of pressure, a lot of heat, a lot of publicity about contraband in the jail,” Spears told Walters, a 24-year Sheriff’s Office veteran.

“You’ve done nothing to bring anyone else to justice, and Keith Kisack is a scapegoat as a result of all the negative press the Sheriff’s Office has received.”

In fact, the videos did not become public until a federal court hearing last year, long after Kisack was booked on the contraband charge.

Along with the illegal horseplay behind bars, the videos show one inmate cavorting on Bourbon Street, apparently after letting himself out for the night with a fellow inmate in tow, armed with a video camera.

Gusman acknowledged last year that the videos had been locked away in a safe since shortly after inmates allegedly shot them in 2009. Cannizzaro’s office brought an indictment against 14 people in the case; most of them have pleaded guilty.

Prosecutors cited that case as evidence that prosecuting Kisack over a cellphone and other contraband is not an anomaly.

Williams ran for district attorney in a race Cannizzaro won in 2008. He won an at-large council seat in a March runoff and has backed away from directly representing criminal defendants since then.

A spokesman for Cannizzaro’s office said the councilman, while under subpoena to appear in court Tuesday, “has been nothing but cooperative throughout the entire process.”

Follow John Simerman on Twitter, @johnsimerman.