Andrew McCollin, 33, of Berwick, Columbia County was first arrested on August 30.
Since then, investigators said a 5-year-old boy disclosed to his parents that he was inappropriately touched by McCollin while at Creative Beginnings Early Learning Center on Route 183 in Bern Township.
McCollin has been charged with aggravated indecent assault of a child, institutional sexual assault - child care, indecent assault, corruption of minors, and endangering the welfare of children.
Detectives said they are continuing their investigation into other possible victims. Anyone with information is asked to contact the district attorney's office by calling 610-478-7171.