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(NBC News) -- Whitney Houston's mother, Cissy, is talking about her daughter's suddenpassing in a new memoir titled "Remember Whitney: My Story of Love, Loss, andthe Night the Music Stopped."

In excerpts obtained by People, Cissy wrote, "I'm angry she died alone, in thoseconditions."

The Grammy-winning singer was found dead, face down in her bathtub, at theBeverly Hills Hilton on Feb. 11, 2012, the night before the Grammy Awards. The final coroner's report listed the cause of death as accidentaldrowning and "effects of atheroscleroticheart disease and cocaine use." Thedocument also indicated that Houston had cocaine, marijuana, Xanax, Benadryl andmuscle relaxants in her system when she passed away.

"She started partying and she didn't really know how to stop. I used towonder what she was doing at night, where she was," Cissy also wrote. The elder Houston also wrote that herdaughter "hid" from her, and that she doesn't blame the singer's ex-husband,Bobby Brown, for her drug problem.

"I blame him for the way he treated her," she wrote, according to the excerpts published in People, "but I don't blame him for herdrug problems."

Watch the TODAY show Monday for Cissy Houston's appearance.