Joseph Nicol (Superintendent of the Bureau of Criminal Identification and Investigation for the State of Illinois) along with Cortlandt Cunningham, Robert Frazier and Charles Killion (of the Firearms Identification Unit of the FBI Laboratory in Washington D.C.) each examined the shells found at the Tippit scene and Oswald's revolver, which he ordered from Seaport Traders, Inc. Each of these experts determined that the shells were linked (through ballistics) to Oswald's revolver, to the exclusion of every other weapon in the world.