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Whitney Houston was "unconscious and unresponsive" when she was pulled out of her bathtub by a member of her staff Saturday afternoon, Beverly Hills police said Monday.

Police said in a news conference that they had concluded their preliminary investigation and cleared out of the Beverly Hilton, where Houston had been found. They declined to comment on any specifics, including the condition of the body or the room, and said no additional information would be released until the Los Angeles County Coroner had completed its investigation.

A hearse under heavy police escort arrived late Monday at the New Jersey funeral home officials say is handling the arrangements for Houston.

The hearse traveled from Teterboro Airport, where officials had told The Associated Press Houston's body would arrive on a flight from the Los Angeles area.

Several officials familiar with funeral planning say arrangements are being made by Newark's Whigham Funeral Home, which handled the 2003 funeral of Houston's father. They spoke to the AP on Monday on condition of anonymity because they weren't authorized to speak for Houston's family.

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The family raised the possibility of holding a wake Thursday and a funeral Friday at Newark's Prudential Center, which hosts college and professional sporting events and seats about 18,000 people. City officials were awaiting the family's arrival to complete the funeral planning.

"We are devastated by the loss of our beloved Whitney," Houston's family said in a statement through the singer's publicist, thanking fans for their outpouring of support. "This is an unimaginable tragedy, and we will miss her terribly."

The coroner's investigation remains ongoing, and the source of prescription drugs found in Houston's room could be a focus. Earlier Monday, a law enforcement official told FoxNews.com that Houston, 48, may have died after consuming a cocktail of prescription drugs and alcohol.

"It looks like it was a lethal combination of prescription drugs and alcohol, but it's still to early to rule out other causes. That's just what it's looking like now," the official, speaking on condition of anonymity, told FoxNews.com.

The official said bottles of different prescription drugs, including anti-anxiety medication, were found in the singer's hotel room.

Initial reports claimed the family had learned of the details surrounding her death from the Los Angeles County Coroner, but the office has denied that it told the family that her cause of death was related to drowning or prescription medication.

Deputy Coroner Ed Winter said he was unable to release any details surrounding the cause of her death because the city of Beverly Hills placed a security hold on the case and testing was still going on. Winter reportedly said Houston could have died from a heart attack or embolism, but that it was too early to speculate.

The autopsy reports have not been released and could take up to eight weeks before going public.

Houston's death comes after widespread reports of boozing and erratic behavior in the week leading up to the Grammys on Sunday.

FoxNews.com learned that Houston was a mess when she showed up to Hollywood hotspot Playhouse on Feb. 2 around 10.30 p.m. to support her on again-off again boyfriend Ray J, who took over the turntables as guest DJ.

"She was a total wreck. She drank cognac and champagne, and seemed completely out of it from the moment she arrived until the moment she left," an insider told FoxNews.com. "Yet at the same time she seemed like she was enjoying herself with her friends. She went to the smoking patio a few times throughout the night and was also seen roaming around throughout the club and even ventured walking upstairs to the smaller room."

In the days before her death, similar scenes were reported. People.com reported that Houston raised eyebrows after checking into the Beverly Hills Hilton on Wednesday and appeared "out of it." Over the course of the next few days, the pop diva was spotted looking noticeably disheveled, with wet hair and mismatched clothes, waving her arms around frantically and wandering aimlessly through the hotel, all while smelling of alcohol and cigarettes.

And in what turned out to be her last ever performance on Thursday night, Houston was seen acting erratically, looking worse for wear with blood dripping down her leg, at a pre-Grammy bash for Kelly Price at the club Tru Hollywood. Multiple reports suggested she got into a tequila-fueled confrontation with former "X-Factor" star Stacy Francis after finding Ray J chatting with Francis.

Houston's daughter Bobbi Kristina Brown was with her at Tru Hollywood and has been having her own troubles since her mother's death.

Brown, 18, was taken on a stretcher out of the Beverly Hilton on Sunday, the same hotel her mother died in on Saturday.

It was Brown's second visit to the hospital since her mother died, People.com reported. The first time was late Saturday night when a source told the website she was "having a complete breakdown." Brown was treated and released both times.

TMZ also reported that the day before Houston was found dead in her bathtub, Brown fell asleep in a bathtub in the same hotel. According to TMZ sources, friends of Brown tried knocking on her door repeatedly Friday night, but she didn't answer. They then called security to get them to unlock the door and help them get Brown out of the tub.

This year had been expected to be the year that Houston got it together, finally reviving the movie career that made her a multi-platform star back in 1992, when she starred in “The Bodyguard.”

The 48-year-old recently wrapped, as both star and executive producer, the movie "Sparkle," a remake of the 1976 Motown-era drama of the same name. It was slated to be released in August.

"Based on her music alone, people lost the faith, but there was speculation that when she came back to the big screen she would regain the momentum in her career,” Billboad.com editor M. Tye Comer said.

Howard Rosenman, an executive producer on the film told The Hollywood Reporter: “This would have been a big, big comeback, she is so brilliant in it.”

Like fellow superstar Michael Jackson, Houston’s comeback may be post-mortem. Sony Pictures has announced it will still release “Sparkle” on Aug. 17. Billboard reported that the singer’s final recordings will be in the film.

FoxNews.com's Jana Winter, Newscore  and the Associated Press contributed to this report.