Richard Hyerczyk, 54, was charged in January after pleading guilty to sending harassing letters to police officers, government officials, schools, private individuals and religious institutions in the area between November 2003 and December 2012.
Hyerczyk admitted to mailing a letter on April 21, 2008 that threatened to kill Chicago Police Department officers and members of their families, officials said. The letter followed news reports that police had shot and killed a cougar on Chicago's North Side, addressing the force as "Dear Cougar Killers."
Hyerczyk also admitted to drafting a second letter referencing a severely injured former Chicago police officer by name, police said. He admitted to printing multiple copies of the letters and sending them to various universities in Chicago as well as a Chicago police officer and the executive officer of the Fraternal Order of Police lodge in Chicago.
Hyerczyk faces a fine of $10,000 and will begin his sentence on July 29, followed by three years of supervised release.
