By Marice RichterDALLAS (Reuters) - A woman and her two teenage daughters found dead inside a suburban Fort Worth home on Sunday were likely killed by the woman's former boyfriend, who then took his own life, police said on Tuesday.The three family members were identified as Xiomara Leon, 34, and her daughters, Linda Gonzalez, 18, and Yasmine Zavala, 13. Leon and Gonzalez were shot multiple times and Zavala was strangled, according to the Tarrant County Medical Examiner's office.Samuel Morales, 36, was also found dead inside the home in the Fort Worth suburb of Crowley. The medical examiner did not disclose his cause of death but police said it appears he killed himself."Our on-scene investigation revealed the possibility of self-inflicted gunshot wounds but we are still awaiting the official results," police said in a statement on Tuesday."From the initial and ongoing investigation we are leaning on the theory that this was in fact an unfortunate and tragic murder-suicide case classified as domestic violence," police said.A 9-year-old boy found alive in the house is staying with relatives. He phoned a relative on Sunday to say a man was trying to kill himself inside the home. The relative then called authorities to investigate, police said.Crowley Police Chief Luis Soler said Leon had been involved in a romantic relationship with Morales for the past four years. He is not the father of Leon's three children.Soler told the news conference, where he had to pause to choke back tears, that the boy did not witness the killings."The lone survivor of this tragedy, a brave 9-year-old boy is doing as best as he can under the circumstances," Soler said.(Writing by Jon Herskovitz; Editing by Sandra Maler)Join the conversation about this story Click here to read full news..