Chicago police officer Thomas Wortham IV was an Iraqi war veteran gunned down in front of his parents' home in Chicago's Chatham neighborhood home three years ago, the Chicago Tribune reported.
The suit was filed in Mississippi where the Smith & Wesson handgun was sold at a pawn shop in an illegal straw purchase in May 2007, the Tribune said.
The handgun then was sold again illegally by a gun trafficker who supplied handguns to the Gangster Disciples street gang in Chicago, and ended up in the hands of four alleged gang members, the Tribune reported.
The four accosted Wortham outside his parents' home and tried to rob him of his new motorcycle.
The newspaper said Wortham pulled his own handgun and identified himself as a police officer. Wortham and his retired police officer father got into a gunfight with the four, and Wortham and one of his assailants were killed, the Tribune said.
The Smith & Wesson that is the target of the suit was found at the scene.
The suit says Ed's Pawn Shop and Salvage Yard failed to follow guidelines on how to detect a straw purchaser, the newspaper said
In a straw purchase, a buyer without a criminal past buys a gun for someone else who would not pass a background check.
The Brady Center to Prevent Gun Violence is assisting Wortham's family in the suit and announced it in Chicago.