An MS-13 snitch detailed an attempted hit on a 16-year-old boy Tuesday, telling a Brooklyn federal jury how the gang’s alleged leader ordered up the kill — and promoted him after the bungled shooting, which left the victim paralyzed.

Jose Gonzalez, 24, testified that his former gang boss Melvi Amador-Rios — who is standing trial on murder and other charges — told him he had to kill someone in order to move up in the ranks of the Centrales Loco Salvatruchas clique of MS-13.

“[He] pulled me over to the side and told me it’s my turn,” Gonzalez told jurors of the conversation, saying it took place shortly after he turned 18, when he was a low-level member, or “chequeo,” in the crew.

When Gonzalez said he asked Amador-Rios what he meant, the accused leader replied, “to go do a killing.”

Amador-Rios didn’t care who was murdered — but said “it had to be” a member of the rival 18th Street Gang, Gonzalez testified.

So on Oct. 22, 2016, Gonzalez and two other chequeos confronted Luis Serrano in Jamaica, Queens, believing the teenager was a member of the rival gang.

“We started beating him and he tried to run — and the minute he tried to run Kevin shot him from behind,” Gonzalez told the court of admitted gunman Kevin Paniagua.

“Then he fell face down on the ground and started having convulsions,” Gonzalez said of the victim.

“Kevin tried finishing him off but the gun didn’t fire,” he testified. “Then he tried again but the gun didn’t fire.”

Gonzalez said he and the other two assailants took off, stashed the gun in an abandoned house and later met up with their comrades at a Jamaica bar.

In a recording played by prosecutors, Amador-Rios could allegedly be heard telling Gonzalez he’d been promoted from the rank of chequeo to that of “homeboy” after helping in the attack on Serrano — who survived but was left a paraplegic.

“In any event, you have the pass to be a homeboy, alright?” Amador-Rios told Gonzalez.

Serrano, now 22, took the stand on Monday — the first day of the trial — telling jurors he’s lived with constant pain ever since the shooting and had to undergo four surgeries, as recently as March.

He denied being part of the rival gang, but said he was friends with two members and had posed in pictures with them flashing their gang sign.

Serrano, who entered the courtroom in a motorized wheelchair, recalled how on the day of the shooting, his three attackers had stopped him, asked if he was an 18th Street Gang member and “started beating me up.”

The next thing he remembered was waking up in a hospital bed.

Serrano said he was hospitalized for nearly nine months recovering from the gunshot wound to his skull.

Amador-Rios is also accused of ordering the hit of 16-year-old Julio Vasquez, who was stabbed more than 30 times and nearly decapitated.

Vasquez was lured to Alley Pond Park in Queens on May 16, 2017 by confessed killers Josue Leiva and Luis Rivas — acting on the orders of Amador-Rios, who believed the teen was cooperating with law enforcement, prosecutors allege.

The boy’s body was discovered later that month by a birdwatcher who stumbled upon his mutilated corpse in the park.

During opening arguments Monday, Amador-Rios’ criminal defense attorney Murray Singer claimed his client was innocent, telling the jury, “it’s not a crime to be affiliated with MS-13.”