LOS ANGELES — Prosecutors are prepared to seek an indictment of Michael Jackson's doctor, Conrad Murray, on a charge of involuntary manslaughter in the pop star's death, The Associated Press has learned.

A law enforcement source who spoke on condition of anonymity because the investigation remains open said today Murray would be prosecuted on a theory of gross negligence alleging that his treatment of Jackson was an extreme departure from the standard of care normally followed by physicians.

Miranda Sevcik, a spokeswoman in Houston for Murray and his lawyer, Edward Chernoff, said the doctor had no comment and reiterated he neither prescribed nor administered anything that should have killed Michael Jackson.

Jackson died at his Los Angeles home in June while under Murray's care as the singer prepared for an ambitious concert schedule.

The district attorney's office is waiting for the Los Angeles police to turn over the case before presenting it to a grand jury.

Before an indictment can be sought, the person said the Los Angeles Police Department will follow the formality of presenting the case to the district attorney.

Both agencies have been working on the case along with the U.S. Drug Enforcement Administration and the California Bureau of Narcotics Enforcement since Jackson died in June.