CHICAGO (AP) — The widow of a slain Chicago Police Department commander has filed a lawsuit against the website used to sell the gun tied to her husband’s death.

The Chicago Sun-Times reports Erin Bauer, wife of Cmdr. Paul Bauer, filed the lawsuit against in U.S. District Court in Milwaukee.

The 9-millimeter Glock pistol allegedly used to kill Bauer in 2018 was sold by a Madison, Wisconsin resident to a Milwaukee resident. The lawsuit claims the gun later made its way through the “criminal marketplace” to Shomari Legghette, who is charged with first-degree murder in the death of Paul Bauer.

The lawsuit alleges Armslist negligently allowed sales of weapons without background checks. Armslist officials haven’t responded to requests for comment.