CHICAGO (CBS) — A Waukegan man has been charged with sexually assaulting multiple girls, some as young as 5, dating back 20 years.

Waukegan Police said they began investigating 54-year-old Eliseo Calderon as a possible rape suspect based on an anonymous complaint, and located five victims between the ages of 5 and 8.

Police said detectives believe the sexual assaults happened between 2000 and 2006 in Waukegan.

Calderon was arrested Tuesday, and has been charged with four counts of predatory criminal sexual assault. He is being held in the Lake County Jail on $1 million bond, and is due back in court on June 24, according to jail records.

Police asked anyone who believes they have had inappropriate contact with Calderon to call Waukegan Detective Tim Ives at 847-599-2678.