Satanic Rituals & Sex Abuse Claims — Mariah Carey's Estranged Sister To Spill All

It's Mariah Carey's worst nightmare! The superstar singer's sister, Alison, is making explosive claims about her famous family as she recovers from decades of drug abuse, RadarOnline.com has learned.

Alison, 54, is receiving treatment at a sober house in upstate New York, according to insiders.

Said a source close to the famous sibling, "She's been clean and sober for a while now, and she's starting to remember a whole lot of stuff about her childhood, her upbringing and a lot of things that happened."

The source claimed, "It's some pretty heavy duty stuff."

Indeed, Alison has even claimed to have detailed memories of devil worshiping and racial problems between Mariah and her father, the insider alleged.

As RadarOnline.com reported, Mariah's brother Morgan had said that the rmama Pat, 79, forced Alison and Mariah to participate in "horrible" and "evil" satanic rituals that sometimes turned sexual!

Now, a close friend of Alison's named David Baker has claimed Alison is ready to speak out, too.

"For most of her life, Alison has had only vague memories of the abuse she endured as a child," Baker wrote on his blog. "As a means of self-protection, her mind suppressed recollections of the horrific events she was exposed to and made to take part in."

"But now, as her brain recovers from the injury she received in a still-unsolved attack in her own home, details of that abuse are coming to the surface."

As RadarOnline.com reported, Alison landed in the rehab facility more than a year ago,  after a mystery man stole jewelry from her apartment, and she woke up with a three-inch gash in her head and a busted mouth.

As for her relationship with Mariah, the two have been estranged for years, even though the HIV-Positive mother of four has begged Mariah for help.

But Baker says he's getting down to the truth about the family's hidden secrets, and will soon reveal all!