Los Angeles ( CNN ) -- Investigators of singer Whitney Houston 's death 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 , sources close to the investigation said Friday . Authorities , however , said they 're still reviewing additional medical information that will be used in their final ruling on her cause of death , and Houston 's toxicology report should be complete `` on or around March 23rd , '' the sources told CNN . Officials are still trying to speak with Houston 's only child , Bobbi Kristina Brown , 18 , before closing the case , the sources said . Investigators have contacted her relatives , but it 's unclear whether the daughter will agree to be interviewed , sources said . The daughter was interviewed briefly by Beverly Hills police the day her mother died , but she was too distraught to offer helpful information , the sources said . She was taken twice to a Los Angeles hospital briefly after her mother 's death , a source close to the family said last month . 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 annual Grammy Awards in Los Angeles . Last month , officials with the Los Angeles County coroner 's office said her body had no visible signs of trauma and foul play was n't suspected . Her cause of death was listed last month as `` deferred , '' officials said . More official details on the investigation have n't been released because the Beverly Hills Police Department was granted a `` security hold '' on the case , the coroner 's office said . Common in high-profile cases , the hold restricts the release of information in a case . Authorities have said that police and fire officials were called to Houston 's room at the Beverly Hilton after her unconscious body was found in the bathtub , just hours before she was to attend a pre-Grammy party at the hotel . Houston won six Grammys and sold 170 million albums , singles and videos over her career . A Los Angeles County coroner official last month downplayed the suspicion that drugs had played a major role in her death . Assistant Chief Coroner Ed Winter said that `` not many prescription bottles '' were found in the singer 's hotel room after her death . The amount of medications recovered by investigators was less than usually present in deaths attributed to overdoses , Winter said . `` I know there are reports that she maybe was drowned or did she overdose , but we wo n't make a final determination until all the tests are in , '' he said last month . In recent years , the singer 's accomplishments were overtaken by her struggles with drug addiction .
Investigators have contacted all the doctors and pharmacies connected to Houston , sources say . Nothing criminal has been found so far in her case , sources say . Toxicology tests could be performed by October 30 or so , sources say . Houston , 48 , died in her Beverly Hills hotel room ; she had battled substance abuse .