A Delaware grand jury returned a sweeping indictment Monday against a pediatrician accused of serial child molestation.

The indictment returned by a Sussex County grand jury charges Dr. Earl Bradley of Lewes with more than 400 counts of criminal conduct. More details about the charges were to be released at an afternoon news conference.

Bradley was arrested in December and initially charged with 29 felony counts for allegedly abusing nine children, but state prosecutors have said there could be as many as 100 victims.

Investigators have said Bradley videotaped some of the attacks with which he is charged, some of which occurred in exam rooms decorated with Disney themes.

Some alleged victims were no more than 6 months old.

Bradley is being held with bail set at $2.9 million. His medical license was permanently revoked by the state Board of Medical Practice last week.

Attorney General Beau Biden scheduled a news conference Monday afternoon to discuss what his office described as "progress made in the investigation and prosecution of the case ..."

Biden, who was in Dover presenting his agency's budget proposal to the legislature's finance committee, declined to discuss the indictment with The Associated Press before the news conference.

After years of suspicions among parents and questions about his strange behavior from colleagues, Bradley was arrested after a 2-year-old girl told her mother that the doctor hurt her in December when he took her to a basement room after an exam.

The case has shocked the close-knit coastal community of Lewes and the central Delaware town of Milford, where Bradley closed an office in 2005 after police investigated him.

Biden and Gov. Jack Markell have ordered reviews to determine whether doctors, hospitals, state agencies or law enforcement authorities failed to comply with a state law that requires all such entities to report to the medical licensing board in writing within 30 days if they believe a doctor is or "may be" guilty of unprofessional conduct.