So I decided to spend close to an Hour ‘Googling’ all sorts of phrases such as ‘3d printed gun crime’, ‘crime committed with 3D printed gun’, etc. How many crimes could I find which were reported online being committed with a 3D printed gun, in the history of the world, on every continent? The answer was one, and that was on the TV show ‘Elementary’, when Lawrence Pendry used a 3D printed gun to murder his wife.
There's also an episode of CSI where a 3D printed gun was used to commit a murder.