(CNN) -- A social worker in Switzerland has confessed to sexually assaulting more than 100 disabled children and adults, authorities said Tuesday.(Feb. 2, 2011)

The 54-year-old man, who was not identified, said the assaults took place over a 28-year span in nine institutions where he worked as a therapist. He is from Argovie district in northern Switzerland, according to a statement from the regional public prosecutor of Bern-Mittelland and Bern cantonal police.