Kevin Warren said the expanded search radius was necessary after efforts to get public infrastructure funding for the Arlington Heights site hit a dead end.

Bears president and CEO Kevin Warren wrote an open letter to fans Wednesday in which he threatened to move the team out of Chicago. The Bears have been trying to construct a new stadium in Cook County,

The team has been in Chicago for more than 100 years, having moved to the city in 1921 from Decatur, Ill., where they were founded as the Staleys in 1920.

Arlington Heights has remained the logical landing point for a potential move. Besides the land, the Bears are paying the village hundreds of thousands of dollars to cover outside consultants’ evaluations of the proposal. The team has estimated some $855 million in public money would be needed for infrastructure costs to support a stadium there.