A Bronx serial killer who came to the United States during the 1980 Mariel boatlift from Cuba — and then lured victims to their deaths with promises of cheap designer blue jeans — has pleaded guilty to his third murder.

Jesus Aguilero, who is already behind bars for two murders, suddenly switched his not-guilty plea in the 1981 killing of 35-year-old mom Tolila Brown last week.

Aguilero, 61, reversed his plea partly because details of his other horrific murders could have been discussed in court, virtually sealing his fate anyway.

“The entire family is just thrilled,” said Brown’s daughter, Robin Dynoe, 52. “It brings us closer to closure.”

Aguilero — a criminal who came to the United States during the mass boatlift of Cuban refugees, some of whom had been released from jails and mental health facilities — would lure his victims to remote locations in The Bronx in the 1980s by promising them impossibly good deals on Calvin Klein and Jordache jeans.

He was put behind bars after being convicted in the 1981 killings of Guillermo Graniela, 30, and Josefina Cepeda, 24.

Then, in 2009, NYPD Detective Malcolm Reiman linked him to Brown’s murder with fingerprints and DNA evidence at the scene.

“It feels like there’s so much evil in the world — and this is one case where it didn’t win,” Dynoe said.

After pleading guilty, Aguilero will be sentenced to 15 years to life, which will run concurrently with the two life sentences he’s already serving.

He’ll be up for parole in 2026.

“There’s no way on Earth that he would be released, but whatever glimmer of hope he wanted to have, he still has,” said his lawyer, Javier Solano.

Aguilero is also believed to be responsible for the death of Janet Agosto, 20, in 1982.