It happened at a home in the 3600-block of New Hope Church Road in Turkey on Monday.
Relatives told ABC11 that Carlos Vasquez shot his daughter, Itzel, in the home and then killed himself.
"Yeah, that's really tough. It hurts, you know? It's sad," said John Vasquez, who is Carlos Vasquez's nephew.
The nephew said a decision by Vasquez's estranged wife, traveling from Texas, could have set Carlos off on Sunday.
"He was all happy she was coming, and she went back to Texas and that made him sad," said John. "I guess that made him kill his daughter and himself."
Sampson County investigators won't say much about what they're calling a death investigation. However, while they wait for autopsy results, the victims' relatives have this request:
"Pray for us. Yeah, just pray for us. That'd help us a lot," said John.