Emergency personnel continued their search Friday for an autistic 7-year-old boy who vanished from his home in the Wood County town of Saratoga.

Authorities said Benjy Heil was playing in the basement, and when the family realized about 6:45 p.m. Thursday that he was gone, they searched for about 15 minutes and then contacted authorities.

Wood County sheriff's Sgt. Randal Dorshorst said searchers continued their work through the night using flashlights and bloodhounds.

About 100 law enforcement personnel and volunteers were involved in the search, Dorshorst said. The Spirit of Marshfield Helicopter assisted until 9:10 p.m. when visibility problems grounded it.

A search party regrouped Friday morning.

"We're going to continue hopefully until we find the boy," Dorshorst said.

The search centered on a campground near the family's home and also on a nearby creek.

Rescue boats were used to search the Wisconsin River, which is about 400 yards from the home.

The rescuers were gathering information from the boy's mother, Cindy Heil.

The family expressed concern that the boy will not respond if called, so emergency workers must visually locate him.