As fans await autopsy results that may not come for weeks, speculation raged that pop legend Whitney Houston may have died from a lethal cocktail of prescription drugs and alcohol. Houston, who possessed one of the greatest-ever singing voices and sold more than 170 million records, fought a long and public battle with substance abuse after her career and personal life went off the rails. She was found dead on Saturday afternoon, at the age of just 48, in her bathtub in a suite of the Beverly Hilton hotel. Houston’s body was released Monday and the body was to be flown to her native New Jersey for a funeral. Celebrity website TMZ said it had learnt from unnamed “family sources” that the singer died from a lethal combination of prescription drugs and alcohol. A friend who saw Houston on Thursday, two days before her death, told that the superstar seemed “upbeat and joyful” and not apparently under the influence of drugs. But the Los Angeles Times reported that Houston had behaved erratically during an appearance that day. Though she greeted people with a warm smile, she appeared dishevelled, with mismatched clothes and dripping-wet hair. According to the report, the singer flailed her hands frenetically as she spoke, skipped around the ballroom in a childlike fashion and wandered aimlessly about the lobby. In a 2009 interview Houston admitted that she laced her marijuana with rock cocaine. Houston most recently checked into rehab in 2011. Sales of Houston’s records have soared after her sudden death, with ‘I Will Always Love You’ the top seller on iTunes. Houston’s family issued a statement before the Grammy show, saying: “We are devastated by the loss of our beloved Whitney. This is an unimaginable tragedy and we will miss her terribly.”