A 22-year-old cold case has been solved in New York City regarding the murder of a four-year-old girl whose identity was unknown. Now we know her true name is Anjelica Castillo, not Baby Hope as she had been nicknamed. Her cousin, Conrado Juarez, an illegal alien from Mexico who was 30 at the time, has admitted to the murder and has been arrested.

Anjelica’s body was found in a cooler by the side of a road in 1991. The child was emaciated and had been sexually assaulted.

Kudos to the police whose remarkable persistence over more than two decades solved the murder.

Below, posters about the case were placed around the neighborhood last summer to jog memories.

According to the following article, police believe Anjelica’s mother was willing to help Juarez (pictured) dispose of the body because she feared deportation. She never reported her child was missing.

‘Baby Hope’ cousin admits fatal sex attack, New York Post, October 12, 2013

It was a murder that wrenched the hearts of New Yorkers and baffled the city’s best detectives and prosecutors for two decades.

On a summer day in 1991, the body of an emaciated 4-year-old girl was found naked and bundled with twine inside a filthy cooler near the Henry Hudson Parkway.

Investigators called the girl “Baby Hope” — and on Saturday their own never-flagging hopes were fulfilled when they finally cracked the case.

The turning point came this summer, in a laundromat, when one woman overheard another woman say that years ago her little sister had disappeared.

The first woman had also seen one of the “Baby Hope” fliers police continued to post, and called the cops.

The tip led to the arrest of Conrado Juarez, 52, who sources said was a Mexican illegal alien dishwasher at the Bleecker Street restaurant Pesce Pasta.

Juarez was the girl’s cousin, and was staying with her ina crowded Astoria apartment, officials said.

Now in custody for murder, he has made what sources called a detailed confession to sexually assaulting and smothering Anjelica Castillo — the girl in the cooler’s real name.

Juarez told cops that on the night of her death, he came home drunk, according to Jerry Giorgio, a former detective on the case who has seen the confession.

“It was nighttime, and she was in the hallway for some reason — maybe she was going to the bathroom,” Giorgio said. “He said he just took her by the hand and she went with him.”

“She may at one point have started to yell or scream, looking for help. That’s when he put the pillow over her face.”

Juarez told cops it was his now-deceased sister, Balvina Juarez, who suggested they put the body in a cooler and take it by livery cab to Washington Heights, where it would rot for more than a week, according to a source.

“A tip produced a lot of investigative work, and with great detective work we were able to track people down and interview them,” Police Commissioner Ray Kelly said.

Cops recently tracked down Anjelica’s mother, also a Mexican immigrant, in Washington Heights.

The mom has nine other children by three men, and never reported her child missing. Finally confronted by investigators, she blamed the father, who had custody at the time, said one law-enforcement source. The girl was being cared for by her dad’s sister, who was Juarez’s mother.

“She’s a piece of s–t,” one law-enforcement source said of the mother. “She tried to put all responsibility on the father.”

Law enforcement sources believe she kept silent for fear of deportation; she told cops she feared the “abusive” father.

Anjelica’s sister, now in her 20s, told police she remembers traveling to Mexico with her father after leaving the girl with her mother, police sources said. She never saw her ­sibling again, she told police.

“Investigators never stopped searching for the person who ended this young girl’s life,” DA Cyrus Vance said, noting that the original prosecutor, Melissa Mourges, now heads the DA’s Cold Case Unit and is still on the case.

Juarez was ordered held without bail at his arraignment Saturday. His lawyer complained that he had been questioned without representation for nearly 14 hours.