All That Glitters - S5.E12

A rich man called Barry Ryan comes to town. He is out with some horses when Luke, who is nearby, hears a shot. Barry has been shot and is taken to hospital. But Jack has a problem, it seem no one was out there except Barry - and Luke. Jack finds out Luke once killed a cop, and puts him in jail. Finally it turns out Barry was trying to kill himself, and Jack and Luke are friends again.