The Medical Board of California is investigating a doctor who, according to documents, prescribed all 11 medications found in Anna Nicole Smith's hotel room the day she died.

Board spokeswoman Candis Cohen says Dr. Khristine Eroshevich is under investigaton, but would provide no other details.

Anna Nicole Smith, a reality TV star and former Playboy Magazine Playmate of the Year, was found unresponsive February 8 at a hotel-casino in Florida.

Eroshevich, a friend of Smith's, had traveled with her to the southeastern U.S. state.

Documents from the Florida medical examiner's office revealed that more than 600 pills, including 450 muscle relaxants, were missing from prescriptions no more than five weeks old.

Khristine Eroshevich has not returned telephone calls requesting information.