The girl's mother was asleep when authorities called her at home, and had not realized her daughter was missing from their mobile home, Vanorsdale said.
"It's a parent's nightmare when a parent goes to bed, thinking their home is secure," Jones said.
The girl, whose name was not released, told investigators she did not know her abductor.
The girl and her two brothers, ages unavailable, had gone to bed about 9:30 p.m. Monday and the mother went to sleep a short time later, Vanorsdale said.
The mother and daughter both said the outside door to the house trailer had been locked Monday night, but Vanorsdale said it can be opened by pushing.
The door did not have a deadbolt lock, he said.
Vanorsdale would not speculate on how the attacker knew the girl lived in the trailer or how he knew the door could be forced open.
The attacker carried the sleeping girl outside without waking other family members, Vanorsdale said. The girl, used to being carried while asleep by a baby sitter, did not awaken immediately.
The girl was able to show Vanorsdale the route along which she was driven, he said.
"She's a very intelligent little girl," Vanorsdale said. "She was better able to provide us information than some adult witnesses we've had."
The girl did not know what time she was taken from the trailer, Vanorsdale said.
Deputies would not specify where the girl had been taken, saying only that it was somewhere in western Jefferson County.
The girl was sexually assaulted by her abductor at a remote location near a creek, Vanorsdale said.
An examination of the girl later at City Hospital in Martinsburg confirmed a sexual assault had occurred, Vanorsdale said.
The girl believed she had been held for hours, Vanorsdale said.
No weapon was displayed and the man did not threaten her, he said.
The girl was able to give a description of the attacker and his car, he said.
The man was described as white, about 6 feet tall, with a heavy build, black, collar-length hair with a black moustache and facial hair on his chin, Jones said.
The man had a large scar from his sternum to his navel and a scar on his back that he claimed was from a gunshot wound inflicted by a cousin when he was a child, Jones said.
The man had a tattoo on each forearm. One tattoo was described as a soldier with a strap across his chest. The other was not described.
He wore a black baseball cap, a black T-shirt with a logo on the front and blue pants, the sheriff said.
He drove a tan or yellow, two-door car. The car had reclining seats and the right door did not work properly. The car possibly has tags beginning with "OK" and the number 97 on the plate.
Investigators spent the day interviewing the girl and her mother, Vanorsdale said.
Deputies have several people they wish to question, he said.
Anyone with information may call the Sheriff's Department at 1-304-267-7000.