Authorities are investigating whether the man suspected in 17 rapes along the East Coast is responsible for more attacks.

The Associated Press reported that 39-year-old Aaron H. Thomas admitted to investigators that he began committing sexual offenses in 1991, when he was 19. The earliest attack attributed to the "East Coast Rapist" occurred in Prince George's County in 1997. Assaults have been reported in Maryland, Virginia, Rhode Island and Connecticut.

Police in Fairfax, Prince William, Prince George's and Loudoun counties said Tuesday that no new victims have arisen since Thomas was arrested in New Haven, Conn., on March 4. But police have said they believe more cases exist.

Thomas pleaded not guilty Tuesday in New Haven Superior Court to a 2007 rape.

- Emily Babay