LOS ANGELES (MCT) — Los Angeles County coroner’s officials said Monday they have not established a link between prescription drugs and the death of Whitney Houston, adding such a determination could only come after toxicology tests are completed.

Houston was found in the bathtub of her suite at the Beverly Hilton Hotel, and officials said they are trying to determine whether she drowned.

A member of Houston’s entourage found her unresponsive Saturday afternoon and called authorities. Beverly Hills Fire Department paramedics performed CPR for about 20 minutes before declaring her dead, officials said.

People who were briefed on the probe Sunday said drowning was one of several scenarios that investigators are exploring. The sources stressed that investigators still have many unanswered questions, particularly about what Houston was doing in the hours before her death.