A company acted negligently in selling the weapon used in a Christmas Eve shooting that left two New York volunteer firefighters dead, according to a lawsuit filed Tuesday.

The semi-automatic rifle was used by William Spengler Jr. on Dec. 24, 2012, during a pre-dawn ambush in which he killed two West Webster firefighters and wounded two others. The gun was purchased at a Gander Mountain store by his neighbor, Dawn Nguyen. Spengler couldn’t buy the gun because he was a felon.