More in Whitney Houston: Death of a pop diva “The family is making arrangements,” Assistant Chief Coroner Ed Winter said Monday|But they are making arrangements and sometimes it takes a couple days.” An autopsy on the singer was completed Sunday; however the coroner is not officially saying what killed the six-time Grammy winner|”At this time her cause of death is deferred and we are finishing with all of our testing and it will be an ongoing investigation,” Winter said|Houston, 48, was found unresponsive Saturday afternoon by a member of her entourage in the bathtub of her fourth floor hotel room at the Beverly Hilton|Law enforcement sources told CBS News that while there were no illegal substances found in Houston’s hotel room, there were prescription drugs|Authorities said the most likely theories for Houston’s death are that she died of a heart attack or a prescription drug overdose, but no official determination has been made, CBS News correspondent John Blackstone reports|The Beverly Hills Police Department has issued a security hold barring the coroner’s office from releasing details surrounding her death while toxicology tests continue|Detectives say Houston had been at the Beverly Hilton with a large entourage of family, friends and co-workers preparing for Clive Davis’ annual pre-award show bash at the same hotel|Houston’s ex-husband, Bobby Brown, who was performing with New Edition in Mississippi when Houston died, issued a statement Sunday regarding her death}