you must immediately wonder who. >> right. well, you wonder if it's a completely random act, some stranger and it was a mistake or an accident, or you develop a list of people that might have a reason to have shot him. >> reporter: to police, it didn't look random. nothing was taken. the killer struck with precision accuracy and got clean away. but there was something that intrigued detective voth that night. it was a clue they found in bill mclaughlin's closet. >> we do a search of the house with the permission of kevin. we're told there are weapons in the closet upstairs. when you come across that many weapons, it becomes surprising. >> reporter: bill was an avid gun collector. he kept dozens in his newport beach house. not just antiques, revolvers, including seven modified m-16 assault rifles. dangerous stuff in the wrong hands. >> we didn't know if somebody maybe was upset with the sale of a gun or something.