So sad! A Hollywood private investigator is claiming that Whitney Houston was murdered by drug dealers and a new surveillance video proves it. Paul Huebl says he handed over evidence to the feds, that shows the 48-year-old singer was killed over a drug debt she previously had. The medical examiner ruled that she drowned in her bathtub at the Beverley Hilton hotel after taking marijuana, a cocktail of cocaine and other legal drugs. Could this all be real? See more details after the jump! Biz Baby