Close friends of the couple told The Post that the Florida man who killed his girlfriend with a knife and then shot himself while their baby daughter cried in a crib nearby recently found out that she had been cheating on him.

Carlos Diaz, 25, killed Amanda Hicks, 26, in the Port St. Lucie apartment they had just moved into with their 11-month-old daughter, Alani, three weeks before. Amanda was a well-liked teacher.

Diaz then killed himself with a gun on May 26. Sources told The Post that Hicks recently ended a pregnancy because his family was not sure who the father was.

“She said that they were working through it,” a lifelong friend of Hicks told The Post. “But I think that was just one of many things that made him angry, and he just lost it. A blind rage.”

Hicks, who also wanted to be a bikini model, met Diaz when they both worked at a school in Port St. Lucie about three years ago. They fell in love quickly.

“They were in love,” said a reliable source. “Amanda had been with some bad boyfriends who were very controlling. She was very happy with Carlos, though. They became friends because they both cared a lot about teaching and kids.

Hicks never knew her father, and her mother died years ago after a long battle with cancer. Not long after they started dating, she moved in with Diaz, his parents, and his sister in a small apartment.

Even though they often got into heated fights that were made worse by alcohol, Hicks’ friends thought she had finally found a good partner.

“He was the best boyfriend she’d ever had,” said a close friend. “In public, he was very nice to her and gentle with her. But he was a bit of a hothead, and that was kind of in the background.”

Before they got married, both Hicks and Diaz had problems with drugs, alcohol, and getting in trouble with the law. In 2020, Diaz was charged with assault after a fight in a bar. In 2019 and 2021, Hicks was charged twice with driving while drunk. At one point, he was told to wear an ankle monitor.

The arrival of Alani with brown eyes brought the two of them closer together. Sources say that Diaz had cleaned up some of his drug problems and had been able to focus on school for the past year. He was getting ready to become a full-time teacher.

Several sources say that Diaz found out that Hicks had been cheating on her a few months ago. She thought the incident was nothing, but her boyfriend was very angry about it. Friends noticed that at the time, Hicks deleted her social media pages.

Sources said that Hicks was pregnant, and even though she said the child was Diaz’s, his family didn’t believe her. She had an abortion after that.

“We knew he had a history of being aggressive,” said a source. “So we were worried. But she told us that they were dealing with it and that everything would be fine.

But Hicks’s relationship with Diaz’s family kept getting worse. A source said that Hicks would drink too much, which made things worse in the small apartment.

Hicks, Diaz, and Alani moved into the Port St. Lucie apartment to give their young family more space while they tried to fix their relationship.

Neighbors told The Post that the couple seemed friendly and calm, and that they were always gushing over their child. Hicks got to work decorating a small outdoor area with rocks, flowers, and a small vegetable garden.

“She worked really hard on it,” said a neighbor who talked with Hicks for 45 minutes a few days before the tragedy. She was proud of it.

Hicks casually talked to her neighbors about her job as a reading teacher. She told them that it was hard for her to get students excited about reading, but that she was still very committed to their education.

Others said that there were no obvious signs of trouble between the newcomers, but that they would sometimes be friendly one day and strangely quiet the next.

A source said that Diaz was planning a way out, even though everything seemed calm on the outside.

A source said, “He wanted full custody of the baby and was trying to figure out how to get it.” “He was going to break up with her, but she didn’t know it.”

At about 11:50 p.m. on May 26, Diaz called a family member several times, but the person didn’t answer or didn’t hear the call, police said.

About an hour later, a neighbor said she heard piercing screams coming from outside as a storm raged. “We thought it was just a fight because that happens a lot around here,”.

At 12:47, a crack that sounded like a gunshot was caught on another resident’s Ring camera system.

“There was so much rain and thunder that night,” a neighbor was told by a local resident. “He didn’t call the police because he didn’t know what it was,” we were told.

When Diaz didn’t answer his phone the next morning, a family member called the police to make sure he was okay.

After hearing Alani’s faint cries from inside the apartment, the police finally broke down their locked front door.

There, they found Hicks dead from being stabbed and Diaz dead from being shot a few feet away.

The wailing baby was still in her crib just a few feet away from her parents. She has since been placed with Diaz’s parents.

“We are all still processing,” a friend of Hicks said. “We’re in shock, we can’t believe that he would do this. That beautiful baby was the spitting image of both of them. It’s just tragic.”

A picture of a smiling Alani dangled Thursday from the rearview mirror of a car parked outside the Diaz family apartment in Stuart.

A man at the home declined to comment.