Search continues for missing 3-year-old near Arcadia, Mo.

ARCADIA, Mo. -- Frustrated rescue workers and volunteers spent a second day Tuesday searching miles of rugged woods, hills and ponds, still hopeful they'd find a missing 3-year-old boy alive.

But as nightfall arrived and rain began to fall, the search for Joshua Childers turned ever more desperate.

Joshua wandered away about 11:30 a.m. Monday from his home near Arcadia, a small, secluded town near the border of Madison and Iron counties. Police were called 45 minutes later. A search began that lasted through the night and into Tuesday.

By Tuesday afternoon, hundreds of volunteers who showed up to help were mostly watching and waiting because so many professional emergency workers were assisting.

The best clue so far came Monday evening when a searcher found a tennis shoe. Joshua's parents confirmed he was wearing the shoe when he slipped away from home.

Madison County Sheriff David Lewis said the shoe was found nearly a mile from the family's mobile home that sits along rough, rural terrain in the Mark Twain National Forest. Rescue crews fanned out in the area where the shoe was discovered.

The Missouri State Water Patrol searched three ponds with divers and dragging. Sonar equipment was being brought in. No clues were found.

Lewis remained confident the 35-pound boy was still alive.

"I don't know why he wouldn't be," Lewis said. "It wasn't that cold last night."

But the weather was turning worse as nightfall approached, with forecasters calling for a chance of heavy rain. Police pulled in many of the volunteers but sent out every available search dog. Police helicopters circled the area.

Lewis said it would be easy for a small boy to get lost in those woods.

"You can't see 20 yards in front of you there," he said. "This is very rugged terrain, very rough, with thick underbrush."

Joshua's father works an overnight shift and was home sleeping late Monday morning. His mother was watching the child but was briefly distracted. That's when the boy got out, wearing a dark blue and green T-shirt, pull-up diaper and tennis shoes.

Police arrived and put out a call for volunteers. Hundreds showed up -- some on horses, some on donkeys, some on all-terrain vehicles or with their own dogs to help.

"It hits pretty close to home," said Randy Johnson, 31, of nearby Bismarck. "When I heard about it I told my wife I had to come down here and do something."

In fact, it was perhaps too many people. Lewis decided to send volunteers out only in small groups, partly to keep them from getting lost or hurt and partly to make sure he kept people fresh in case the search dragged on for days.

Lewis said the boy's father was among those searching the woods. The mother was waiting at home, in case the child returned.

Asked how they're holding up, the sheriff said, "They look a little dazed, actually."