Bobbi Kristina Brown, the daughter of deceased singer Whitney Houston and Bobby Brown, was using heroin and other drugs in the months before being found unresponsive and face-down in her bathtub on Jan. 31, People reports.

According to People's sources, Brown, 21, was "regularly" using heroin, cocaine and Xanax in the months leading up to the incident, as well as drinking heavily.

Also Read: Whitney Houston's Millions: What Bobbi Kristina Brown May Leave Behind and Who Stands to Gain

People cites one source as saying that Brown had been "in and out" of rehab since her mother's Feb. 11, 2012 death, but hit stumbling blocks in her recovery because she was "distraught" over the upcoming third anniversary of Houston'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," the source said.

Also Read: Bobbi Kristina Brown Newest Developments: Nick Gordon Speaks, Tracheotomy Performed

Bobby Brown's attorney has not yet responded to TheWrap's request for comment.

Brown was placed in a medically induced coma and put on a ventilator after being rushed to the hospital from her Roswell, Georgia, home. She reportedly underwent a tracheotomy this week, in order to provide another air passage.

Also Read: Bobbi Kristina Brown's Medical Condition Explained: 'Complete Recovery Would Be Almost Impossible'

The bathtub incident bears eerie similarities to Houston's death at age 48. Houston was found submerged and unconscious in a bathtub at the Beverly Hilton Hotel prior to her mentor Clive Davis' pre-Grammys party. The Los Angeles County coroner's office later determined that Houston had drowned to death, with heart disease and cocaine use contributing to her death.