HOUSTON (AP) — Police in Houston searched Thursday for a shooter who killed three people, including a young girl, and wounded another child who was able to call her grandmother to summon help, authorities said.

The shooting happened late Wednesday at an apartment complex, Houston Assistant Police Chief Patricia Cantu said.

When authorities arrived, they found a man, a woman and a girl believed to be about 5 to 7 years old who were fatally shot, Cantu said. Police believe the woman was the mother of the two girls, but investigators were still determining the man’s relationship to them.

The wounded girl, believed to be about 10 years old, was in stable condition, police said.

Police do not yet have a suspect description but the victims may have known the shooter because there were no signs of a break-in, Cantu said.

“This was a very, very tragic scene. We’re sending out prayers to the family,” Cantu said. “This was a very difficult scene not only for us but for the family as well.”