A Brooklyn parolee will spend 25 years to life behind bars for gunning down an innocent 16-year-old boy because the teen’s older brother was in a rival gang.

Ralief Bradford, 30, shot Justin Richey in the heart a day after his 16th birthday after confronting him on a Cypress Hills street on July 15, 2018, and falsely accusing him of being in a gang.

Bradford, whom a jury found guilty of murder and weapon possession in March, was sentenced by Brooklyn Supreme Court Justice Phyllis Chu on Tuesday.

Justin was helping a neighbor with household chores at Pine St. and Blake Ave. when Bradford and two accomplices, both still at large, confronted and surrounded him, prosecutors said.

Bradford is a member of the Front Side Bloods, a Bloods subset active in the Cypress Hills Houses. Justin’s older brother was in the Crips, but the teen had no gang ties, according to prosecutors. Instead, he was remembered as a community-minded, helpful youngster who for years volunteered at the Cypress Hills Community Center.

Bradford and his cohorts were looking for his brother, but they settled on young Justin. One of them put him in a chokehold and slammed him to the ground, while another struck him with a metal cane, prosecutors said.

Bradford pulled out a gun and opened fire, hitting the teen in his chest and heart. Justin ran for his life, but collapsed a half block away.

Senior Assistant District Attorney Sarah Jafari referred to Bradford’s actions as “utterly despicable and senseless” in a May 8 sentencing letter.

“The defendant killed Mr. Richey with wanton disregard for the immense [effect] his death would have both on Mr. Richey’s family and the community,” she wrote. “Mr. Richey was a teenager living in a gang-infested neighborhood and the defendant murdered him on a public sidewalk, in broad daylight, in front of others for no discernible reason besides Mr. Richey’s older brother’s gang affiliation.”

Bradford, who also goes by the name Zabar Beebe, was out on parole at the time of the shooting for a pair of gun-related crimes, one of which ended in police shooting him in the rear.

That incident happened on Jan. 4, 2013, when he was 18 years old — he ran away from NYPD officers after they approached him about a possible trespass, then pointed a gun at them before dropping the weapon, Jafari wrote.

He wound up being sentenced to 16 months to four years behind bars as a youthful offender. But police tied him to an earlier shooting, with the same gun he pointed at the cops, as part of a gang takedown investigation. That landed him a five-year prison sentence, and he was released on parole in April 2017, a little over a year before Justin’s murder.

“Justin Richey was brazenly and senselessly shot to death by this defendant in broad daylight on a Sunday afternoon,” Brooklyn District Attorney Eric Gonzalez said Tuesday. “Justin was killed just one day after his 16th birthday. I hope today’s sentence brings a measure of solace to his heartbroken family and friends.”

Bradford’s lawyer Julie Clark declined to comment Tuesday.