PEKIN, Ill. (AP) — The family of one of the four people killed in a shooting at a Waffle House restaurant in Nashville, Tennessee, is suing the suspected gunman's father, accusing him of negligence.

The Peoria Star reports that the family of victim Joe Perez filed their lawsuit Monday in Tazewell County, Illinois, which is where defendant Travis Reinking lived before moving to Nashville and where his father, Jeffrey Reinking, still lives.

Authorities say that Travis Reinking exhibited multiple warning signs that he was mentally unstable before he moved from Illinois to Nashville, and his guns were seized and Illinois gun license was revoked. But they say the guns were returned to his father, who gave them back to his son when his son moved to Tennessee. Prosecutors say he used one of the guns, an AR-15, in the attack.

Jeffrey Reinking's lawyer, Joel Brown of Peoria, didn't reply to a message seeking comment.

Travis Reinking is charged with murder.