Casey Parker

Casey Parker, a character in the Law and Order: Investigation series is the main antagonist of episodes 9-12

He is a gun rights activist who had a partnership with the CEO of Printworx, Keith Mox. After Mox cut off their partnership to develop 3D printed guns, Casey took advantage of Hubert Lui and used his paranoia that his wife and Keith were having an affair to have him murder Keith in the Printworx office.

Depending on the choices you make during your testimony, he either gets off scot free or is charged as an accessory to murder.