*California investigators probing the death of Michael Jackson will not file charges against seven doctors other than Conrad Murray who treated him, authorities said Wednesday.

The physicians were under investigation by state Attorney General Jerry Brown’s Bureau of Narcotic Enforcement, spokeswoman Christine Gasparac told the AP. One doctor whose name was not released has been referred to the California Medical Board for prescribing drugs to a Jackson alias, she said.

Murray, Jackson’s personal doctor, has pleaded not guilty to felony involuntary manslaughter in the singer’s death. Authorities say he gave Jackson a mix of sedatives, including a powerful anesthetic that killed him.

Los Angeles police who investigated the death had asked state and federal investigators to look into the prescribing practices of doctors who previously treated the 50-year-old pop star.

The federal Drug Enforcement Agency has also stopped investigating the actions of any other Jackson doctors, agency spokeswoman Sarah Pullen said.

“I am very disappointed,” said attorney Brian Oxman, who represents Michael Jackson’s father Joe Jackson in a wrongful death lawsuit against Murray. “The misuse of medications by Michael Jackson in the last years of his life was excessive and to fail to bring that to the public eye is ignoring reality.”

The state investigation included the search of a prescription drug database that tracks doctors who prescribe controlled substances. The database also monitors the quantity and recipients of those drugs.