Whitney Houston 911 Call

In the tape, the caller -- a member of the security team from the Beverly Hilton -- reports a 46 year old female who was found in a bathroom at the hotel.

At first, the caller is unsure if Whitney was breathing ... but later reports she is not breathing.

The security member says he was alerted to the situation by a female who was in the room ... and says the woman was "irate" and kept hanging up on him.

As we previously reported, Whitney's official cause of death is listed as "accidental drowning" -- but heart disease and cocaine use were contributing factors. According to the final autopsy report, Whitney may have overdosed.