Norwich — A then-staff member at the Arc New London County faces a sexual assault charge after he allegedly touched an adult female client on the autism spectrum sexually and told her he would “get mad” if she told anyone.

William C. Levander, 32, of 313 Prospect St. was charged Friday on a warrant with second degree assault involving a person unable to consent. He was arraigned Monday in New London Superior Court and released on a $100,000 bond with an order to have no contact with the alleged victim.

Police said they were contacted Jan. 21 by staff at the agency who had reported that a 29-year-old female client had stated that a staff person responsible for her care had kissed her inappropriately. During an internal investigation by Arc staff a few days earlier, the alleged victim told staff Levander had touched her sexually inappropriately more than once.

Police observed a forensic interview done by staff of the New London Children’s Advocacy Center, during which the victim described alleged sexual encounters with Levander and said he had shown her photos on his cellphone of strangers engaged in sexual activity. The victim said Levander allegedly pulled her clothes down on one occasion and told her “he wanted to make love to her,” according to the police affidavit. He also allegedly told her “not to tell anyone or I’m going to hurt you. Keep this between us. It never happened,” the affidavit said.

Levander declined to be interviewed by police. According to the arrest warrant affidavit, during interviews with Arc staff, Levander said he and the alleged victim at times were alone together, including in her bedroom when he was trying to “calm her down.” He denied any physical sexual contact and said he never asked her to keep a secret and did not show her sexually explicit photos.