Relatives of a young mother fatally shot in the neck in her Brooklyn basement apartment say they had accepted her boyfriend — who is now being sought by cops for the slaying — as part of the family

Tatiana Pettus, 24, was murdered in the apartment where she was living with the boyfriend and his mother on Foster Ave. near E. 29th St. in Flatbush about 11:30 p.m. Tuesday, police said. Cops say she was slain during a fight with her boyfriend, who is the father of the victim’s 1-year-old daughter.

“It was a total shock to us,” the victim’s uncle, Sabata Pettus, told the Daily News. “She brought him into our family and we accepted him wholeheartedly. He was quiet but he was one of ours. We can’t believe it.”

Neighbors in the four-story apartment building heard an argument coming from the basement apartment and called 911. Medics rushed Tatiana to Kings County Hospital, but she could not be saved.

Cops have identified the boyfriend and are actively looking for him.

The couple, who had been together several years, appeared to have a “solid” relationship, Tatiana’s uncle said.

“We don’t even know how it got to this, because neither one of them, especially him, this is not something that they showed us,” he said. “It wasn’t his character. This is a very mild-mannered young man. Very quiet, very keep-to -himself. Not no knucklehead in the street. There was no reason for us to fear him.”

“This is something that came out of the blue,” he added. “This is a total, total shock to us and it’s just unexplainable.”

Cops have been scouring the crime scene and surrounding area for surveillance footage that could help them track the shooter’s escape.

“I pray [he] turns himself in,” the uncle said. “He was part of our family for a long time. Tati brought him into the family and we embraced him.”

Tatiana’s father will now likely raise her 1-year-old daughter, the uncle said.

“She’s gonna grow up without her parents,” he said of the baby. “She lost her mother to senseless violence and whatever happens to the father … it’s unfortunate.”

“This is an unfortunate situation where young men now don’t have mental intelligence and there’s too much access to weapons. That’s how something like this just happens,” he added. “The congressmen, the citizens, the judges — they need to do a better job of getting control of gun access.”

The couple worked night shifts together at an Amazon warehouse hub. Tatiana worked there first and helped her boyfriend secure a job there too, her uncle said.

Tatiana Pettus. (Facebook)
Tatiana Pettus. (Facebook)

“This is a very big loss for our family. In a family of men, she was our baby girl,” Sabata added. “Tatiana was what brought the whole family together. She was a very intelligent, go-get-em, loving person.”

Tatiana was looking forward to a family reunion in North Carolina next week.

“Yesterday at 7 a.m. I got the worst call ever from my dad that my favorite baby cousin Tatiana Pettus was murdered,” the victim’s cousin, Tamorya Meeks posted on Facebook. “I hung up and instantly  broke down because no way. I just talk to her last week and she was so excited about coming down south for the family reunion.”

“Everybody was looking forward to bringing the babies together for the family reunion,” the uncle added.

Now relatives will be traveling to New York to bury the young mother instead.

With Thomas Tracy