EAU CLAIRE, WI (WTAQ) - Prosecutors now say an Eau Claire doctor sexually assaulted at least 14 children during his medical practice – and police are still investigating other reported incidents.

60-year-old David Van de Loo was charged Tuesday with 13 new felony counts – almost all of them for first and second-degree child sex assault.

He was initially charged in October with exposure and second-degree assault, both felonies, after the parents of a 16-year-old boy complained that their son received sexual contact during a routine medical exam.

Publicity about the case prompted more victims to come forward. Authorities said the molestation occurred while Van de Loo served as a pediatrician and sports medicine specialist at the Mayo Clinic in Eau Claire.

Van de Loo posted a $50,000 cash bond after a court hearing Tuesday in Eau Claire County, with the condition that he not have unsupervised contact with minors. Van de Loo is due back in court January 15th, when a judge will determine if there’s enough evidence to order a trial.

The investigation first began in August. The Mayo Clinic said it reported Van de Loo’s conduct to the state’s Medical Examining Board on September 11th – and the clinic fired him the next day.

Meanwhile, Van de Loo and the Mayo Clinic both face a civil suit filed by a 21-year-old man who said the doctor sexually-abused him at least 10 times between 2004 and last year.