The boyfriend of a young mother shot to death in the Brooklyn apartment they shared with their one-year-old daughter has been arrested for her murder, cops said on Wednesday.

Tahj Nelson, 23, was arrested and charged with murder and criminal possession of a weapon on Monday, a week after 24-year-old Tatiana Pettus was fatally shot in the neck inside their basement apartment on Foster Ave. near E. 29th St. in Flatbush, police said.

The couple lived in the apartment with their daughter and the suspect’s mother. Nelson was at large for about a week before he was arrested in Brooklyn Monday around 9:15 a.m.

“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 apartment and called 911. Medics rushed Tatiana to Kings County Hospital, but she could not be saved. The couple’s daughter was being babysat elsewhere by relatives when the slaying occurred, Tatiana’s uncle said.

The couple, who had been together several years, appeared to have a “solid” relationship, Sabata 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.”

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.

“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.”

Nelson is being held without bail until his next court appearance.