The search for a 7-year-old autistic boy went through a fourth day Monday before the threat of stormy weather halted it.

Lt. Dave Laude of the Wood County Sheriff's Department told volunteers waiting to go out that it would be unsafe for them to join the search. He asked them to return Tuesday and bring as many others as possible to help.

Benjamin "Benjy" Heil had been playing in the basement of his home in the town of Saratoga last Thursday when his family realized he was gone and called authorities.

The home is about 400 yards from the Wisconsin River, but Nekoosa Fire Chief Ken Hartje said it was unlikely the boy would be found there.

Dog teams swept through area near the river Sunday night and found no trace of the boy's scent, he said.

"We have combed the search area and recombed and recombed it some more," Hartje said.

Hundreds of volunteers and rescue personnel braved weekend rain and humidity to join the search for the boy, who has been known not to respond when his name is called.

Searchers used horse-mounted trackers, aircraft and boats, while a team of divers searched the river.

Area residents have been asked to repeatedly check their homes, vehicles and anywhere else the child might seek shelter or food.

"He's very resourceful as far as getting food," said Jay Shroda, a Sheriff's Department investigator. "If he's hungry, thirsty, he will seek out water."

Hartje said medical officials have told him that if Benjy finds water, he can survive in the elements for more than two weeks.

The Red Cross and the Salvation Army are providing food and drinks for searchers.

Janet Keyzer, a former neighbor of the Heils, said she was still hopeful the boy will be found.

"I've talked to hundreds of people. None of us whatsoever have begun to give up, yet. Never," said Keyzer, of Nekoosa. "The mood when you're going out is so pumped. Coming back you just feel like you let him down."