SHEBOYGAN, WI (WHBL) - A Plymouth man is facing a charge of repeated sexual assault of a child for sexual contact that he had with his sister going back to their childhood. The man, who won’t be identified to protect the identity of the victim, is 27. His sister is 28. According to the criminal complaint which was filed Wednesday, an investigation began three weeks ago when the woman, described as “cognitively delayed," contacted the Sheboygan County Sheriff’s Department. She said the sexual contact began years ago and continued until she was 18. The suspect has been charged with incidents which occurred between April of 1994 and December of 2000. He is facing up to 40 years in prison.