Bobbi Kristina Brown was allegedly suffering from a severe drug problem that included heroin and cocaine addiction in the days before she was found face down and unconscious in a bath tub late last month.

According to People Magazine, the 21-year-old daughter of Whitney Houston and Bobby Brown has also been accused of regularly using Xanax and drinking heavilyy, often becoming so wasted she would slur her words and appear to be incoherent.

Bobbi was found unconscious in the Georgia home she shared with boyfriend Nick Gordon almost exactly three years after her mother's lifeless body was pulled from a bath tub in a Beverly Hills hotel where she was staying. Investigators later determined drugs were in Whitney Houston's body at the time of her death.

As the day of the anniversary of her mother's death neared, sources alleged Bobbi's dependency on drugs only seemed to grow. She now remains hospitalized at Atlanta's Emory Hospital on life support and has failed to regain consciousness since being rushed to the emergency room on Jan. 31.

"How thin she had gotten is an indicator," a source told the magazine of just how much Brown seems to have been struggling since her mother's death. "This girl was trying hard, but she didn't have any support system. She was still dealing with a lot of grief over her mother."

Another source said Bobbi had been "in and out of rehab since the death of her mother.

Police, meanwhile, have launched a criminal investigation of the events leading up to her being found comatose after authorities discovered several unexplained bruises on her body.

HollywoodLife.com reported the probe centers around Gordon, and since Bobbi has been hospitalized, family members have banned him from being able to visit her.

Throughout her ordeal, Bobby has maintained a regular vigil at his daughter's bedside.