Houston's sister-in-law says the late singer was "chasing a dream" She and Bobbi Kristina Brown, Houston's only child, speak to Oprah Winfrey Daughter says she can still hear her mother's voice and feel her spirit sometimes On the same show, Winfrey also spoke to Houston's sister-in-law and friend, Patricia Houston, and her brother, Gary Houston. Whitney Houston, 48, died February 11 in her room at the Beverly Hilton Hotel in Beverly Hills, California, the day before the music industry gathered for the Grammys in Los Angeles. But in recent years, her struggles with drug addiction overshadowed her accomplishments. I gotta carry on her legacy. ... Sources close to the investigation into the singer's death told CNN on Friday that officials were looking to speak with her daughter before closing the case. They said it was unclear whether Bobbi Kristina would agree to be interviewed. She was interviewed briefly by Beverly Hills police the day her mother died, but she was too distraught to offer helpful information, the sources said. Investigators have wrapped up the logistical part of their inquiry by having contacted all physicians and pharmacies with ties to Houston, and nothing so far appears criminal, the sources said. Authorities are reviewing additional medical information that will be used in the final ruling on cause of death, and Houston's toxicology report should be complete "on or around" March 23, the sources said. Last month, officials with the Los Angeles County coroner's office said the singer's body had no visible signs of trauma and foul play wasn't suspected. Her cause of death was listed as "deferred," officials said. Common in high-profile cases, the hold restricts the release of information. Authorities have said that police and fire officials were called to Houston's hotel room after her unconscious body was found in the bathtub, just hours before she was to attend a pre-Grammy party. A coroner official last month downplayed the suspicion that drugs had played a major role in Houston's death. Assistant Chief Coroner Ed Winter said that "not many prescription bottles" were found in the singer's hotel room.