Michael Jackson's doctor returns to court in April to find out the date for the next main step in the case - a proceeding that will drag out the evidence the prosecution believes will reveal his "gross negligence" as the direct cause of the pop star's death.

The Los Angeles County coroner ruled Jackson's death a homicide, caused due to a combination of drugs, primarily propofol -- a powerful anesthesia -- and lorazepam. Murray is accused of giving Jackson a fatal dose of an anesthetic to help him sleep. Jackson died June 25. If convicted, the doctor could face up to four years in prison.

Dr. Conrad Murray pleaded not guilty Monday and as a consequence was granted release on $75,000 bail.

Also the Superior Court Judge Keith Schwartz has extended an order to Murray ordering him to turn in his passport, rendering a restriction on his outside the country visit. However, he is permitted to travel in U. S.

The prosecutor had suggested he might flee to his native Grenada or to Trinidad where he has a child.

Schwartz told Murray he was restricting his practice of medicine, barring him from using any anesthetic agent, specifically the drug propofol that a coroner's report found was the cause of Jackson's death with other drugs as contributing factors.