Published: Feb 09, 2011 7:26 PM EST
Updated: Feb 09, 2011 4:29 PM EST

ST. LOUIS- The girlfriend of former Anheuser-Busch CEO August Busch IV died at his home after accidentally overdosing on the painkiller oxycodone.

St. Louis County Medical Examiner Mary Case on Wednesday announced results of a toxicology exam for 27-year-old Adrienne Martin of St. Charles, Mo. She was found dead on the morning of Dec. 19 at Busch's estate in suburban St. Louis.

St. Louis County forensics administrator Suzanne McCune said the full report won't be released until the prosecuting attorney's investigation is complete. She would not say if any other drugs were found in Martin's system.

Martin slept at Busch's home the night before her death. He has said he woke up around 11 a.m. and tried to awaken Martin, but couldn't.

(Copyright 2011 by The Associated Press. All Rights Reserved.)