Three teenage girls, including one who was pregnant, have been shot to death by man who then fatally shot himself.
The man also sexually assaulted a 12-year-old girl who later escaped, police say.
No names have been released.
The slayings happened at the home of the gunman's girlfriend in the Houston suburb of Galena Park at about 10.30pm on Saturday.
The girls who were killed were 19, 14 and 13, according to Harris County Sheriff Ed Gonzalez.
The 38-year-old man then attacked the 12-year-old and then told her to run out of the house, Gonzalez said. She grabbed a one-year-old baby girl and fled.
"She ran out of the residence without any clothing" to the home of a neighbor, who called Galena Park police.
"When she ran out she managed to think about it, thankfully, and was able to grab the one-year-old and ran away," Gonzalez said.
Both girls were hospitalized for treatment of injuries that were not life-threatening, according to a statement from Galena Park police.
The investigation has been turned over to the sheriff's department.
Gonzalez said the man's girlfriend was the mother of the 12-year-old and the 19-year-old.
The older victim was the mother of the baby and was pregnant. The sheriff said the girlfriend was not at home at the time of the shootings.
The sheriff said authorities were working to determine the relationships of the other two teenagers who were shot but described them as family members.
Gonzalez offered no suspected motive for the shooting, saying it "makes no sense, it's all tragic."
The U.S. has seen a deadly start to 2023, including six mass killings in a three-week period in January, according to an Associated Press/USA Today database.
It defines a mass killing as four or more people dead, not including the perpetrator.
Six people were killed in a mass shooting Friday in Mississippi and there have been a number of mass shootings in which fewer people were slain, such as Monday's shooting at Michigan State University in which three people were killed and five were wounded.
