An ex-convict who sucker-punched a father of five outside a Las Vegas bar — killing him in an unprovoked attack — is headed to prison, according to a report.

James Beach, 28, must serve 3 to 10 years for the April 2017 death of 45-year-old Luis Campos. He could be eligible for parole in about two years with 339 days of credit for time served at the Clark County Detention Center, the Las Vegas Review-Journal reports.

Campos was standing outside Vanguard Lounge when he was approached by a man — later identified as Beach — who punched him for no reason. The father of five from La Puente, California, collapsed and died four days later from head injuries. He had been in Vegas to be the best man at his brother’s wedding, according to the Las Vegas Sun.

Campos’ uncle, Paul Mancillas, told a judge that Beach — who previously served five years in prison after pleading guilty to attempted murder in 2008 — is a “predator” who will victimize another person when he’s ultimately released from prison.

“He will do this again,” Mancillas told District Judge Douglas Herndon.

Herndon echoed Mancillas’ sentiment, saying the attack was “unfathomable” and difficult to comprehend.

“There wasn’t any kind of fight or anything,” Herndon said. “You just decided to punch this guy as you’re walking past him on the sidewalk.”

Through his attorney, Campos apologized for the fatal assault, calling it a “terrible accident and unfortunate event.”

Campos’ brother, however, criticized the plea deal with prosecutors after Beach pleaded guilty to voluntary manslaughter in February.

“We’re all going to die,” Campos’ brother, Drake Garibay, told Herndon. “But I think what makes it worse is how we die. My family and I have been dealt a life sentence of pain, torment and suffering. Meanwhile, this piece of trash gets the luxury of a plea deal. For what?”