Los Angeles, Feb 5 (IANS): Police have launched an investigation after reportedly finding drugs at the home of Bobbi Kristina Brown, daughter of late singer Whitney Houston, shortly after she was discovered in an unresponsive state in a bathtub at her house in Atlanta.

The Roswell Police Department is said to have discovered the narcotics shortly after the 21-year-old actress was discovered unresponsive Jan 31, family sources have told tmz.com.

While Kristina, who is the only daughter Houston and Bobby Brown, is currently "fighting for her life" in hospital, an investigation has been launched into the circumstances in which she was found after police conducted a second search of the property.

Her husband Nick Gordon and her ex-boyfriend Max Lomas were the first to arrive at the scene, and according to Fulton County Jail records, Max, 24, was arrested early last year on suspicion of drug dealing and was charged with possession and intent to distribute cannabis as well as possession of Alprazolam.

Kristina, who is thought to have spent up to eight minutes underwater, has been placed in a medically-induced coma after being found with "no heartbeat".

Although she is said to have "opened and closed" her eyes a few times Monday, a source close to the family said she remains on a ventilator in the intensive care unit and doctors have warned that they won't be able to tell if she has suffered brain damage until the sedatives can be reduced.