(CNN) Almost a month after Harley Dilly disappeared on his way to school, police believe the Ohio boy's body has been found in a chimney.

"This is not the outcome anyone wanted, but ... we have some closure for the family," Port Clinton Police Chief Robert Hickman said Tuesday.

The cause of death was determined to be compressive asphyxia, Ottawa County Coroner Dr. Dan Cadigan said in a news release. The manner of death has been deemed accidental by the coroner's office.

Harley, 14, was last seen December 20 in Port Clinton as he left for school between 6 and 7 a.m., police said.

At least 75 law enforcement agencies have scoured more than 150 acres with helicopters, trained dogs and search-and-rescue teams, Port Clinton police said.

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