Investigators have contacted all the doctors and pharmacies tied to Houston , sources say . Comment: Toxicology results could be completed by March 23 or so , sources say . 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 . Houston , 48 , died in her Beverly Hills hotel room ; she had battled substance abuse .
Investigators have contacted all the doctors and pharmacies tied to Houston , sources say . Comment: Toxicology results could be completed by March 23 or so , sources say . Houston , 48 , died in her Beverly Hills hotel room ; she had battled substance abuse .