Chicago, Ill., Mayor Richard Daley listens as President George W. Bush addresses the U.S. Conference of Mayors on January 23, 2004, at the Capital Hilton in Washington. (UPI Photo/Roger L. Wollenberg)

The summer house wasn't damaged but a neighbor's multi-million-dollar home was destroyed and another house suffered heavy damage when winds off Lake Michigan fanned the flames, authorities said.

Investigators, who entered the case when it was learned the mayor had received a threatening letter before the fire, said the culprit may be someone protesting the April 14 shooting of a wild cougar on the streets of Roscoe Village in Chicago, the Chicago Tribune reported. The fire occurred 10 days later.

Berrien County Sheriff J. Paul Bailey refused to release the contents of the note but said it led to the investigation that eventually ruled the fire an arson, the Tribune said.

Chicago police shot the cougar after many sightings in the North Side neighborhood. Officers cornered the 122-pound cat in an alley and shot it seven times after it lunged at an officer.