By looking in details at their production methods, the research observes what influence did the manufacturing processes and the mechanical characteristics of the typewriter have on the design of the typefaces. Additionally, it takes interest into the surprising role played by the criminal police. Specialized in the dating and identification of typewriter typefaces for judicial and criminal purposes, forensic experts developed over the years specific methods and compiled rich documentations on typewriter typefaces. Being in direct contact with the type manufacturers to gain first-hand information, they even interfered in the design of some lettershapes. Based on oral history and archival research, this project aims to shed light on this little-known part of the industrial and typographic history.