BARRINGTON, Ill. (STNG)  -- If you want to mail a letter at the Barrington post office, you'll have to go inside.

Barrington-Inverness police are investigating the theft of a blue mail collection box from outside the post office at 1515 S. Grove Ave. in the northwest suburb, according to a release.

The box, located at the south exit of the P.O. Box section of the facility, was taken between 12:15 p.m. Sunday, May 21, and 3 a.m. Monday, May 22, police said.

And taking it was no easy job. The box was bolted to the concrete and would have required a considerable amount of force to dislodge, the release states.

The U.S. Postal Service is offering a $10,000 reward for information leading to the person responsible for stealing the mailbox, the release said.

Anyone with information is asked to call police at (847) 304-3300.