The L.A. County coroner's office has subpoenaed Whitney Houston's doctors for medical and pharmacy records. This is standard operating procedure for virtually all death investigations in order to determine cause of death and whether or not a person had any serious medical conditions, according to Assistant Chief Coroner Ed Winter.

"We've already contacted a number of doctors with requests for records," Winter said.

Investigators found several prescription bottles in Houston's Beverly Hills hotel room where the singer died Saturday. Detectives would not disclose which medications were seized.