The apparent triple homicide was the second in the city in two days.
The bodies in the latest case were found by a man coming home after a night shift at work.
"They killed my family," he told a 911 dispatcher.
Anthony DeLeon told the Fort Worth Star-Telegram that the dead women were his sisters, Kathy DeLeon, 35, and Cynthina DeLeon, 48, along with Cynthina's daughter, April Serrano, 21.
Rosa Guerrero, who waited outside the house with other members of the family, said her Aunt Cynthina was a devout woman and an unlikely victim of violence.
"Anything that can lead to whoever did it," Guerrero said. "We're asking, please."
On Monday morning, police found a 57-year-old man and two other people dead in another house. One of the victims was identified as Ronney Jackson, one of the house's residents, but police had not released any information about the other two Tuesday morning except to say that both were adults.
Kelly Ireland, who lives nearby, told the Star-Telegram the home was "a known drug house with all kinds of drama."