The search for a missing autistic teenager in northeast Iowa entered its fourth day on Wednesday (April 11, 2018).

La Porte City Police Chief Chris Brecher estimates that investigators and volunteers have combed nearly 255 square-miles around the southern Black Hawk County community since Jake Wilson, 16, disappeared Saturday evening. On Tuesday, buses were used to transport groups of volunteers to areas as far away as nine miles outside La Porte City. According to Brecher, authorities are planning to broaden the search in some areas on Wednesday.

“Where we are going to be expanding, we're going to try to be a little particular about it,” Brecher said. “We need a reason to be expanding somewhere. We don't want to be expanding just for the sake of expanding.”

To date, the search for Wilson has involved dozens of law enforcement agencies from all four corners of Iowa and nearly 1,800 volunteers. Black Hawk County Sheriff Tony Thompson says as many as 10 FBI agents and four Iowa Division of Criminal Investigation (DCI) agents have also been working the case, and more assistance is on the way.

“I'm bringing in another discipline team organized through the state called Iowa C.A.R.T., which stands for Child Abduction Response Team. ” Thompson said. “Don't read anything into that other than they have specific expertise in regard to 'If we can't find him, we still have to figure out where he's at right?'”

Thompson said there's no evidence to indicate any foul play or that Wilson's disappearance might be a criminal case. According to investigators, Wilson picked up a dairy treat at a local ice cream shop in La Porte City Saturday evening. Moments later, he went for a walk near Wolf Creek and never returned home.

“We're still treating this (case) as a missing person,” said Thompson, during a news conference late Tuesday afternoon. "We are still processing this with the same diligence, the same methodology, and the same meticulousness that we would any other criminal investigation.”

At the news conference, the sheriff was asked at what point in the search do organizers send volunteers home and let investigators take over.

“We're going to let this investigation dictate that rather than any of us intervene on that," Thompson said. "This incident will tell us when its appropriate to push one direction or another.”

Thompson estimated that investigators have tracked close to 1,000 tips in the case, since the search for Wilson began. .

“We've got some things that interest us,” Thompson said. “We've had a lot of wild goose chases and we don't disparage that. We're tracking everything. I've told you time and time again that nothing is off the table.”

The sheriff remains optimistic that Wilson will be found, even though critical time has passed since his disappearance.

“There are little things every day that gets my hopes up and keeps me fired up,” Thompson said. “We are as much a cheerleader at this point as we are anything because we want the volunteers to keep coming. We want them to be energized and encouraged. We continue to hope and pray for the best. The amount of energy and effort can only be repaid by the amount of energy and effort we apply as well.”

Authorities were planning to use volunteers again on Wednesday and were asking those who could help in the search to report to the La Porte City Fire Station at 8 AM.

Anyone with information on Wilson's whereabouts should call La Porte City police at 319-342-2232 or the Black Hawk County Sheriff's Office at 319-291-2515.