Beverly Hills Police department Public Information Officer, Lt. Mark Rosen comments on Whitney Houston’s death investigation outside the Beverly Hills Hilton Hotel in Beverly Hills

“Oh, no, this is accidental,” Billy Watson told ABCNews.com. “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. Houston’s body left the Los Angeles County Coroner today; ABC News’ New York affiliate WABC reported that it is expected to arrive at the same Newark, NJ funeral home that handled arrangements for Houston’s father in 2003.

Beverly Hills police revealed today that Houston was “underwater and apparently unconscious” when authorities found her in the bathtub of a room in the Beverly Hilton hotel. She was first discovered by a member of her personal staff at about 3:30 pm on Saturday. She was pulled from the tub by members of her staff and hotel security was promptly notified. Fire department officials who arrived found her unconscious and unresponsive; she was pronounced dead at the hotel at 3:55 p.m.

Public information officer Lieutenant Mark Rosen said at a press conference today that police consider Houston’s case a “death investigation, not a criminal investigation,” but added that they have not “ruled out” the prospect that it could turn into a homicide investigation. He declined to comment on any reports about her cause of death.

L.A. assistant chief coroner Ed Winter also maintained at a news conference today that officials do not know the 48-year-old singer’s cause of death. But he confirmed to ABC News’ L.A. affiliate KABC that officials found prescription bottles in Houston’s hotel room. 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. Houston’s official cause of death will not be determined for six to eight weeks, pending toxicology results.

TMZ reported earlier today 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.

Investigators looking into the death of Houston have said that they will be examining the pop icon’s behavior in the hours and days before she was found dead. They have already questioned the singer’s family, friends, and staff.

Meanwhile, Houston’s 18-year-old daughter, Bobbi Kristina Brown, has been struggling with her mother’s death. She was hospitalized Sunday 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.”