Houston's body was released by the Los Angeles coroner earlier today after the completion of an autopsy to determine the cause of her death.
Houston was found "underwater and unconscious" in the bathtub of a Beverly Hills, Calif., hotel room Saturday afternoon, according to Beverly Hills police. Prescription drugs were found nearby, and bottles of champagne and beer were in the adjacent room at the Beverly Hilton Hotel, as seen in photos of the scene obtained by TMZ.
Amid the circumstances of her death, and Houston's history of drug addiction, many have speculated that the singer died after taking a toxic mix of prescription drugs and alcohol.
"You can look at a body and not know (what) the cause of death is,'' said Ed Winter, Los Angeles County coroner's spokesman. "You might have a suspicion, but the person could have suffered a heart attack or embolism."
Results of toxicology tests are not expected to be complete for six to eight weeks.
Earlier today, Houston's entourage moved out of the Beverly Hilton. Sources tell ABC News that many close to Houston have been questioned about her final hours.
There were no obvious signs of trauma or foul play on Houston's body, according to sources with knowledge of the case. And while detectives from the Beverly Hills Police Crimes Against Persons detail are working the case, the department insists this is not a homicide investigation. However, they have not ruled out the possibility that the case could turn into one.
"We're conducting a death investigation and we need to be very clear about that,'' said Beverly Hills Police Department Public Information Officer Lt. Mark Rosen. "We do not know the cause of death, we don't know the circumstances leading up to her death."
Houston's brother-in-law Billy Watson told ABC News that the singer's death was accidental, and certainly not suicide.
"Oh, no, this is accidental," Watson said. "She wouldn't have left her daughter like that. She wouldn't have done that to her daughter."
Watson, whose sister is married to Houston's brother, Gary, also said the family is flying back to New Jersey from California today and Tuesday.
ABC News' New York affiliate WABC reported that the same Newark, N.J., funeral home that handled arrangements for Houston's father in 2003 is expected to handle the singer's arrangements.
Houston's was first discovered by a member of her personal staff at about 3:30 p.m. Saturday, she was underwater and unconscious, authorities said. Shewas pulled from the tub by members of her staff and hotel security was promptly notified. Fire department officials who arrived found her unresponsive; she was pronounced dead at the hotel at 3:55 p.m.
Winter, the coroner's spokesman, confirmed to ABC News' L.A. affiliate KABC that officials found prescription bottles in Houston's hotel room, but he said they weren't "alarming" or "out of the ordinary."
They were all "pretty normal" prescriptions, Winter said, adding, "I have more prescriptions than what was found in her [Houston's] room."
A source told KABC that one of the prescriptions was amoxicillin, an antibiotic commonly used to treat bacterial infections.
TMZ reported earlier that family sources briefed by coroner officials were told Houston likely died from a combination of the drug Xanax and other prescription medication mixed with alcohol.
PHOTOS: Whitney Houston Through the Years
Meanwhile, Houston's 18-year-old daughter, Bobbi Kristina Brown, has been struggling with her mother's death and was hospitalized for "stress and anxiety," a family source told ABCNews.com. She was released Sunday afternoon as her father, Houston's ex-husband Bobby Brown, boarded a plane to L.A.
TMZ reported that on Friday night, Bobbi Kristina fell asleep in another bathtub at the Beverly Hilton. Friends had to contact hotel security so she could be removed from the tub.
Houston, who struggled with drugs and alcohol and entered rehab for the third time last year, reportedly spent Friday night at the bar of the Beverly Hilton hotel with a group of friends. She was at the bar for a long time, drinking and being very loud, according to TMZ.
Houston gave her last performance on Thursday at Grammy nominee Kelly Price's party at Tru, a Hollywood nightclub.
"We laughed and we joked and we cracked up, and we danced and sang," Price said. "She was never more than two feet from me the entire night. I gave her a hug, and while I was talking to her she said 'Give me the mike.'"
"In retrospect it's a much bigger moment than I could have imagined," she added. "It was a big moment just because it was Whitney. The world got a gift in that they got an opportunity to see her perform one last time."
Photos taken later that night show Houston leaving the club looking disheveled and disoriented. She reportedly had blood dripping down her leg and scratches on her body.
"It was a great event and she left sweaty, and I have heard the word 'disheveled,'" Price said. "That's about right. When you stand for three hours and in that time period you are dancing. You would leave a club looking that way.
Price added that Houston "didn't look like she was under the influence of anything. She drank some champagne and toasted Kelly Price's three Grammy nominations Thursday night. That's what Whitney Houston did."
