Targets of Obsession - S11-E15
Continuity mistake: When Justin Bieber gets shot, we see him from the back as he falls back, and his left hand is flailing around with no gun in it. We then cut to him from the front falling backwards, and he's holding the gun in his left hand the whole way down to the ground.
Targets of Obsession - S11-E15
Continuity mistake: Watch the back angle of McCann getting shot. His gun disappears only to reappear in the front angle.
Targets of Obsession - S11-E15
Other mistake: In the shot right after Stokes shoots McCann you can see that Stokes' SW99 has jammed, with a casing sticking out of the chamber.
Answer: He doesn't have the authority to arrest him - when anyone is arrested in the show, a police officer does it. Also he tells Ty that he is going to be submitting his case findings to Ty's insurance company, who would no doubt contact the IRS, who then would have him arrested for fraud etc.