Mayor Robert Smith told council members that he suspended St. John on Monday. St. John did not attend the special council meeting.
St. John's salary is $72,100.
Smith and other city officials declined to comment on the reason for the suspension.
St. John became police chief in August 2007.
Smith declined to comment about whether St. John's job was on the line and what, if any, disciplinary measures would be taken.
St. John declined to comment about his being placed on leave.