Relatives of victims killed in the massacre at Sandy Hook Elementary School have filed a lawsuit against the maker of the gun used to carry out the shootings. The lawsuit accuses Bushmaster of wrongfully selling its AR-15 rifle to civilians when it is designed for military uses, like penetrating steel helmets. The lawsuit came two years and one day after the shooting, which killed 26 people on December 14, 2012. Since then, according to Mother Jones, school shootings have occurred every five weeks on average in the United States.