Until Tuesday, authorities had never said whether they believed Trung “Joe” Le actually hit anyone when he opened fire on Bourbon Street during a melee in the early morning of June 29, 2014.

But at the start of a trial expected to run through the week, Assistant District Attorney Laura Cannizzaro Rodrigue told a jury Tuesday that Le, 22, fired four times with a 9 mm handgun and struck five people — including two friends from Mobile, Alabama, who each got hit in the ankle by the same bullet.

Rodrigue said Le, of Belle Chasse, then took off running before another shooter raised his .40-caliber handgun and unloaded shots through the crowd. One .40-caliber bullet fatally struck Brittany Thomas, a 21-year-old nursing student from Hammond, in the back of her head.

All told, nine others were shot, including one man who swears the 32-ounce frozen daiquiri he was holding saved his life, Rodrigue said.

Yet Le, who claims he fired in self-defense after the other, still-unknown man raised his weapon, isn’t charged in relation to any of the five people authorities say he shot.

Le’s defense attorney, Martin Regan, sought to drive home that point to the jury of six men and six women as the trial got underway.

Le is charged with attempting to murder an “unknown black male,” a reference to the other shooter. He also faces a manslaughter count in Thomas’ death, for allegedly committing a crime during which she was killed. Prosecutors recently tacked on an obstruction-of-justice charge against Le, who sat quietly as Rodrigue described him as the aggressor in a dispute over drugs.

She said Le’s friends had been ripped off a few hours earlier by an armed man in a marijuana deal gone bad. Angry, Robert “Big Red” Benvenuti and Justin Odom called Le and told him to bring his gun to Bourbon Street, Rodrigue said. They were standing at Bourbon and Orleans Avenue when they spotted the man who had robbed them walking past about 2:45 a.m., she said.

Prompted by something, the man turned, walked up to Odom and got “right in his face,” Rodrigue said, before Odom shoved him back. As the man retreated, she said, Le stepped off the curb and fired four times. Later, after fleeing to Mississippi, he typed a note into his phone, all but confessing, she said, despite telling police they had the wrong man.

“ ‘I have committed the worst sin possible, and for what I’ve done, I deserve to burn in hell,’ ” Rodrigue said, paraphrasing Le’s note.

“He knows exactly what he did that night,” she went on. “There were consequences, and he understood that for a minute in time, and that minute came and went. Because believe me, no victim ever got an ‘I’m sorry.’ ”

Among the first witnesses to take the stand was shooting victim Nicholas Williams, of Mississippi. Williams said he was in town for a family reunion on the night of the shooting, standing on Bourbon with his brother, listening to a street performer. He was struck in the leg by a bullet that broke two bones, he said, lifting a pants leg from the witness stand to reveal a screw protruding below his knee.

“It’s painful, emotionally and physically,” he said, choking up. “I don’t do as many activities with the kids as I used to. I just take one day at a time.”

Three other victims also took the stand, though none said they saw who shot them.

“Somebody was asking for a cigarette, I gave it to them, and ‘Shot, shot, shot,’ ” said Ernest Simmons, 19, of New Orleans. “I collapsed and tried to get up, and on my way getting up I collapsed again. I kind of made it to the club where I was safe. I was crawling to it, and somebody dragged me in.”

“What did you think was going on?” Rodrigue asked.

“I’m dead,” he replied.

Three of Thomas’ family members came to court in T-shirts reading “Justice for my sister.” They walked out quietly as Rodrigue and prosecutor Tiffany Tucker played the frantic 911 calls that followed the carnage.

Rodrigue said police might never have found Le if Benvenuti hadn’t been shot in the buttocks and then refused to cooperate with police. Social media posts ultimately led investigators to Le, she said.

Benvenuti is expected to testify that Le acted heroically, defending his friends from a man who appeared to be mentally unstable or intoxicated and who cast aggressive stares into the crowd before zeroing in on the group.

Regan noted that several victims were hit in the lower extremities. His theory: Le shot his target in the shoulder, altering the latter’s aim. Regan called the other shooter, who has never been apprehended, “the Bourbon Street terrorist.”

“But for Trung’s actions, they would have gotten bullets straight in the face,” Regan said. “They would probably be dead.”

Regan argued that while Le took aim only at the other man, the second shooter fired indiscriminately:

“He’s shooting at everyone on Bourbon Street. He’s just, like, machine-gunning everybody at this point — unlike Mr. Trung Le, who shot at one person, directly at the shooter, the terrorist, and hit other people.”

Rodrigue said police deduced who shot whom by where several victims stood in relation to the two gunmen.

After viewing a video of the shooting. Aniya Wiggins of Mobile, Alabama, concluded that the bullet that tore through her ankle — allegedly fired by Le — may have saved her life.

“If I wouldn’t have been shot in the first round, I would have been standing up, so that means I woulda been shot in the back of my head,” said Wiggins, 18.

“Thank you for saying that,” Regan responded.

Follow John Simerman on Twitter, @johnsimerman.