The jurors heard from 58 witnesses, including more than a dozen who came shackled and hoping to have years or decades cut from their prison terms.

They learned the grim details of how a band of teenagers from Uptown and the 7th Ward allegedly joined forces to wreak bloody havoc on rival gang members and bystanders alike, then boasted of their murderous exploits on social media, rap videos and recorded jail phone calls.

They heard from one defendant’s father and a self-described “Mafia wife,” both of them squeezed by prosecutors to testify about a Central City shooting spree that left 5-year-old Briana Allen and an adult passerby, Shawanna Pierce, dead in May 2012.

They never heard an alibi.

After more than two weeks of testimony and some six hours of closing arguments, a jury is set to begin deliberating Thursday in perhaps the most elaborate trial in years at Orleans Parish Criminal District Court.

Demond “Lil D” Sandifer, 19; Sam “Lil” Newman, 19; and Tyron “T-Man” Harden, 21, sat quietly Wednesday as their lawyers sought to unravel weeks of evidence against them in the first case to go to trial among the half-dozen gang racketeering prosecutions that District Attorney Leon Cannizzaro’s office has pursued since late 2010.

At the center of a case that began with a 51-count indictment in 2013, accusing 15 alleged 110ers gang members and associates of 15 murders and several more attempts over three years, was the May 29, 2012, shooting spree on Simon Bolivar Avenue that claimed little Briana’s life as she celebrated a young cousin’s birthday on her great-grandmother’s porch.

Pierce, a 33-year-old mother of three, was driving a rental car four blocks away when a fatal bullet from an AK-47 struck her face, authorities say.

Also at the party, according to witnesses, were several members of the Young Melph Mafia, a group that included one of the suspected targets: Lionel “Lonnie B” Allen, a relative of Briana’s father, convicted drug-dealer Burnell “Baldy” Allen.

Prosecutors claim 110ers Sandifer and Newman, along with Harden of the 7th Ward, circled in a silver Nissan, then jumped out and opened fire, missing their targets while killing the two innocents.

Lacking a gun or any eyewitnesses who fingered the three men or suspected driver Stanton “Nan Nan” Guillory — who may soon face federal charges — the investigation by New Orleans police and a multiple-agency gang unit set up by Mayor Mitch Landrieu’s office relied on a trove of other evidence: phone records, recorded jail phone calls, scores of incriminating posts on Facebook and Instagram, and the crucial statements from a parade of co-defendants who pleaded guilty in the 110ers case, along with other convicts.

In his closing argument Wednesday, Assistant District Attorney Jason Napoli cast the wide-ranging evidence as a window into a cavalier culture of violence in the city.

“The true tragedy of this case is it’s becoming custom. It’s becoming part of our city,” Napoli told the jury. “You’ve seen the attitude that leaves our children dead on the streets. It is an absolute disregard for human life. It’s a game to them. It’s a joke. And on May 29, 2012, they were playing that game. The game’s pretty simple: ‘I’m going to get my crew, you get your crew and we’ll see how many people we can kill.’

“The people who want nothing to do with that game are the people who keep losing the game.”

Attorneys for the three defendants urged skepticism over the prosecution’s attempt to fit various violent crimes under the overall heading of a conspiracy to promote gang activity.

Sandifer’s attorney, Michael Idoyaga, argued that prosecutors were overreaching with a racketeering indictment brought under a state statute that mirrors a federal law created to go after the Mafia.

“What do they do? Are they organized in a way to make a profit? To sell drugs? Run women? No,” Idoyaga said of the 110ers. “We’ve got racketeering without a racket.”

Napoli acknowledged that the 110ers didn’t seem to have much of a drug business or other enterprise to protect, saying they killed largely for pride.

“I wish we were talking about heroin and cocaine, but that’s not why we’re here. The goal here is death,” Napoli said. “It’s not worth it just to kill somebody if you can’t brag about it. That’s the reason this case was so easy for us, because they had to tell everyone about what they did.”

One of Newman’s attorneys, Stavros Panagoulopoulos, showed the jury a chart listing 13 convicts who testified, the prison sentences they are potentially facing and the deals they admittedly hoped to get for their testimony. Five of them face life terms but could see as little as 10 to 20 years.

He argued the 13 were “jumping on a charge,” echoing stories put forth by other convicts to help their cause.

“If we were talking about priests and nuns, we might say they’re above that. These are gentlemen who are pleading guilty to murder — not accidental shootings, but contract killings,” he said. “They had the opportunity to watch as one person, then another, then another cut down their time.”

Outside of a few witnesses, he said, “everyone else has been bought and paid for.”

Napoli and the lead prosecutor, Assistant District Attorney Alex Calenda, have acknowledged that Harden — the alleged AK-47 triggerman — is not himself a 110er. They sought to portray a violent alliance, however, between the 110ers and a 7th Ward band known as the Young Mafia Fellaz, with which Harden was associated, they said.

But Harden’s attorney, Rick Schroeder, described him as an “outlier” in the case, even denying that he was a member of the Young Mafia Fellaz or any other gang.

“The witnesses they put up here were frankly the worst witnesses you could conceive of,” Schroeder told the jury.

Harden didn’t turn up in numerous photos prosecutors displayed of Newman, Sandifer and other 110ers flashing guns, he noted, or bragging in homemade rap videos around Clay Park, a stomping grounds of the St. Thomas-area 110ers.

Harden is named in just four of the 89 “overt” acts that buttress the racketeering conspiracy count in the indictment.

But he may face the biggest stakes. Newman and Sandifer already were convicted of murder and each sentenced to 1 1/2 life terms without the possibility of parole in separate trials last year for killings pulled from the gang indictment.

Newman was convicted of killing 21-year-old Jonathan “Kruga” Lewis just 12 days after Briana and Pierce were killed. A jury convicted Sandifer in August for the 2011 killing of 22-year-old Milton Davis.

Though Napoli pointed to 11 witnesses who implicated Harden in the killing of Briana Allen and Pierce, Schroeder called the evidence flimsy.

“Nobody here is telling you Tyron is an angel, that he’s a saint,” he said. “And if he was my son, I’d kick the s*** out of him.”

But Schroder said Harden’s big mistake, along with running from police in one charged offense in 2011, was hanging out with some people associated with the Young Mafia Fellaz, making him “a likely scapegoat, a likely someone to point at.”

The jury will begin deliberating after Judge Tracey Flemings-Davillier reads them 35 pages of jury instructions Thursday morning.

Follow John Simerman on Twitter, @johnsimerman.