A man in his thirties known online only by his screen-name instantly recognized the gun seized from the suspect in the killing of the UnitedHealth CEO earlier this month. As a photo circulated online ...

Part of the gun that the police believe was used to kill the C.E.O. of UnitedHealthcare was made by a 3D printer using a popular design found online. By Thomas Gibbons-Neff and Aric Toler At first ...

More than a decade after the advent of the 3D-printed gun as an icon of libertarianism and a gun control nightmare, police say one of those homemade plastic weapons has now been found in the hands of ...