P was in his one-year probationary period as a new police officer. P witnessed a fight between two other officers. P told investigators that one of the officers had started the fight. P alleges that the police chief, Zeilmann (D), wanted P to tell the investigators that both officers had been equally at fault. P refused to alter his statement and D wrote a letter to the city's board of fire and police commissioners stating that P had failed to perform adequately during his probationary period and should be fired--and the board fired him. The board had conducted no hearing before firing P. P sued the board and D in an Illinois state court. P claimed the board afforded no due process and its decision to dismiss him had been 'against the manifest weight of the evidence,' 'arbitrary and capricious,' and 'legally erroneous.' P acknowledged that a probationary employee ordinarily lacks the kind of interest that entitles him to a predeprivation hearing, but contended that the collective bargaining agreement between the police department and the department's employees created such an interest. The state court entered judgment in favor of Ds. P then sued in federal court, and the court dismissed for res judicata. P alleged in the federal suit that D’s conduct violated P’s first amendment rights. P appealed.