The Iowa National Guard assisted in the search for missing teenager Jake Wilson in La Porte City on Wednesday (May 16, 2018).

According to La Porte City Police Chief Chris Brecher, the guard provided the services of a CS 47 military helicopter during a training mission. Brecher said the Chinook hovered over Wolf Creek to create down pressure in hopes the disturbance would free up an object trapped under the water. During the operation, two teams in kayaks made their way down the creek to check on any immediate results.

Authorities didn't give any advance public notice of the Iowa National Guard exercise, due to safety concerns associated with a low-operating helicopter. Brecher revealed details of the operation in a press release Wednesday evening.

Jake Wilson / Courtesy: Black Hawk County Sheriff's Dept.

The search for Wilson has been on-going since April 7, when the 16-year-old went for a walk near the creek and didn't return home. Investigators don't know what happened to him.

Wolf Creek has been a primary focus during the search. Brecher said most of the creek has been checked, but the water is filled with piles of large trees and branches that could provide clues to Wilson's whereabouts.

Authorities also had a large excavator in the water Wednesday, removing debris from Wolf Creek. The cost of the excavator was paid for with a grant from the Black Hawk County Gaming Association (BHCGA).

In the release, Brecher said he is "very pleased with the progress that has been made (with the search) thus far."

In recent interviews, the police chief has indicated the possibly of volunteers being used in the search again once flooded areas along the nearby Cedar River dry out. Brecher said some areas along the river remain under water, so authorities are holding off on public foot searches at this time.