It’s not only vigilante libertarians who are taking advantage of 3-D printing to print their own guns (remember when Defense Distributed posted a design for one online?). In Germany, the police are tinkering with the tech as well.
GigaOm reports that German police agencies admitted to buying a 3-D printer "in order to see whether homemade 3-D printed guns are really a threat," and more specifically, if those plastic guns could be sneaked onto a plane. But also, they’re interested in determining whether or not 3-D printed guns might be a useful addition to the force’s arsenal.
Apparently, they’ve been conferring with Australian police about the matter, who conducted tests on 3-D printed weapons in the past--only to have the $35 plastic Liberator firearm they created explode. But it’s likely that as designs and printers improve, and given the difficulty of censuring design plans on the open web, 3-D printed guns will proliferate. So it makes sense for police to adopt the "if-you-can’t-beat-'em-join-'em" mentality and begin grappling with the technology.