Ray J had no idea Whitney Houston was taking cocaine.

The singer is furious after his on/off girlfriend's former sister-in-law Leolah Brown suggested he was to blame for the singer's death in February, as he was in San Diego when she passed away in her hotel room in Beverly Hills. Ray J's spokesperson insisted to website TMZ that the star had "no knowledge" Whitney - whose official cause of death was accidental drowning due to the effects of heart disease and cocaine use - had started taking drugs again.

Los Angeles County Coroner released the official cause of Whitney's death yesterday, and revealed as well as cocaine, traces of marijuana, Xanax, Flexeril and Benadryl were found in her system, although they did not contribute to her tragic passing.

A source connected to the investigation told TMZ.com, it is "very possible" Whitney had a heart attack that caused her to lose consciousness and drown. The heart attack may have been triggered by hardening of the arteries as a result of cocaine use. The coroner also noted that neither foul play nor trauma factored into her demise. A final report is expected to be ready for release within two weeks.