There are some cases where the detective stays long after leaving the job.

For the retired NYPD detective. Christine Casilla, the brutal October The 2014 murder of a three-month-old newborn in the Bronx (by a caregiver who slammed the baby’s head twice against the bedpost) is the case that still haunts her.

“It was horrible,” Casilla, now 49, told The Post. “It broke my heart.”

Casilla was one of the first to respond to the call of a baby at Presbyterian Hospital who was barely breathing.

“The baby had a skull fracture from one side of the ear to the other,” said Casilla, who retired in 2020 and lives in Orange County. “He was on life support for a while.”

“After a while, it was determined that there was no brain activity.”

The baby, Joemill, was taken off life support on November 5, 2014.

“The day they took her off life support, the mother gave me a small Ziploc bag with a little piece of her hair inside,” Casilla recalled.

Since then, Casilla and mother, Barbara Greer, have stayed in touch. At one point, Greer asked Casilla if he could get her the blanket she was wrapping her baby in, but the detective couldn’t find it.

When they met on October 27, on the ninth anniversary of Joemill’s tragic beating, in the cemetery where the boy is buried, Casilla gave him a replica of the blanket he had found on eBay.

“I wasn’t expecting something like this,” Greer said. “I was waiting to see her. “I went down to the ground and she went with me.”

“We were both crying.”

Greer had recently moved to the Big Apple in 2014 from Puerto Rico when she told Casilla she had to go to work and was hoping her then-boyfriend’s sister would see Joemill.

But the sister called and asked Greer if it was okay for her husband to watch the baby.

The mother felt she had no choice.

She was new in town and needed her factory job to keep the one-bedroom apartment where she lived with her boyfriend, who was the baby’s father, and her daughter.

“When I got home, unfortunately, my son was lying in my bed,” the mother told The Post, vividly remembering the unimaginable tragedy as if it were yesterday.

“She said, ‘I was burping him and he hit his head on one of the bedposts,’” Greer recalled through tears. “And then he said, ‘He hit the other side of his head too.’ “My son was covered, as if he didn’t want us to see what they did.”

The mother removed the blanket and saw that Joemill’s face and body had turned a shade of blue. He immediately got into his car and took the newborn to the hospital.

The police officers who arrived at the hospital, including Casilla, arrested Luis Cartagena, who was responsible for taking care of the baby.

Greer said she broke down in tears that night when she met Casilla, who offered the grieving mother heartfelt words of compassion.

“When I first saw it, I started crying,” said Greer, now 42 years old.

Cartagena’s story continued to change as cops pressed him for answers, Casilla said, so he went into detective mode and watched hours of surveillance footage from the mother’s building.

“(Cartagena) said he didn’t know what happened,” Casilla recalled. “I watched eight or nine hours of video and no one entered the apartment. “It never came out.”

He ultimately accepted the crime and pleaded guilty to attempted second-degree murder. He was sentenced to 18 years in prison.

Cartagena, now 42, is serving time at Eastern Correctional Facility in Ulster County with a release date of 2030, state records show.

“I wish it were longer,” Casilla said of the sentence. “This was evil. “The baby had a skull fracture from one side of the ear to the other.”

Today, Greer lives in Massachusetts and has a 6-year-old son. Her daughter is an adult.

“My purpose in telling this is that I want other moms to follow their instincts,” Greer told The Post, breaking down as she spoke. “If you feel like you don’t want to go to work or you don’t trust that person, do what you have to do, stay home.”

“I will live with this forever.”