I can see the family of the deceased winning in court.
This good Samaritan could go to jail.
Nope. He's already been exonerated by local police and FBI. Indiana Law shields him from legal action against him. It's a justifiable homicide. No law was broken.
And the "no gun" policy at the mall is not legally enforceable or criminal unless he was previously asked to leave and violated a misdemeanor trespass code by remaining on the property.