In the “Officer Blue” episode aired on 12 November 2005, you can see how a 3D printer is used to solve a crime.
“A police officer is shot in the middle of Central Park from a building way outside the park. He dies right away. Sadly, the bullet, an important piece of evidence, is buried into the officer’s horse, Blue. Removing might end Blue’s life”
The solution ? Make a CT scan and use it to create a 3D model of the bullet then “3D print” it with a ZPrinter 310 from ZCorporation