WEST VALLEY CITY — A baby sitter has been arrested by West Valley police in the rape of a 5-year-old girl he was watching. Investigators believed the 18-year-old man sexually assaulted the young girl on at least three occasions over the past two months, said West Valley police Capt. Craig Black. Sometimes the assaults would occur while the man was baby sitting the child, other times while he was simply visiting the girl's home, he said. The man was friends with the little girl's older brother and has known the family for years, Black said.