<p>Mayor Daley's Michigan summer home was apparently the target of an arson that badly burned two of his neighbors' homes last month -- and was possibly set by someone angry over the recent killing by Chicago Police of a wild cougar on the North Side, the Sun-Times has learned. </p> <p>The April 24 fire in Grand Beach, Mich., was initially believed to be an accidental brush fire. But police reopened the investigation after learning that a threatening note was sent to Daley's City Hall office, Berrien County Sheriff J. Paul Bailey said.</p>