A police investigation revealed that Dr. Murray was not licensed to prescribe most controlled drugs in the state of California. The steps he had taken to save Jackson also came under scrutiny, as evidence showed that the standard of care for administering propofol had not been met, and the recommended equipment for patient monitoring, precision dosing and resuscitation had not been present. As a result, Jackson's death was ruled a homicide, and Murray was convicted of involuntary manslaughter on November 7, 2011, earning a maximum prison sentence of four years.