Doctor Shrinker
One of the most famous (and many would say infamous) scientists' in the world, Michael Cadmus is a brilliant cutting-edge doctor in the field of biological micronization. He is also, sadly, mad as a hatter and is willing to experiment on human subjects with no qualms whatsoever. Born and raised in Germany to parents who were also highly intelligent scientists, he had much to prove as he grew older. He's known the world over by his infamous nickname, "Dr. Shrinker".
Facing a worldwide epidemic of crime, many police forces in multiple nations have purchased Dr. Cadmus' "Shrink Box". To save jail and prison space, this box shrinks criminals down in size, to between 1 to 6 inches. Once a person is shrunk below 6 inches, their mass density makes them virtually indestructible. However, stomach acid can destroy shrunk person, so if swallowed a shrunk person is doomed!
A person shrunk by the Box must be restored to their original height within 90 days, or their small size will be permanent!
Continued rumors of misuse of the Shrink Box has prompted FBI investigations, but there has been little evidence of "widespread" misuse. However, several cases of abuse have been documented, including one case where a police officer placed a prisoner in his boot and walked around all day with him in it. Another officer put a shrunk prisoner in his jockstrap for several hours. Finally, a lone Sheriff went on duty with two prisoners strapped to his nipple rings.
Finally, the re-bigification process is somewhat painful.