Cheyenne Police wer called to the City Municipal Building around 2 p.m. Monday afternoon, after receiving a call about a suspicious letter found by an employee. Police, Cheyenne Fire, and the Air National Guard HazMat crew were all on scene to investigate.  After a about three hours, it was determined that the contents of the letter sent to Cheyenne Mayor Rick Kaysen was actually ground coffee and creamer.  Officials locked down the building until about 5:40 on Monday.