Revealing mistake: When Grissom and the Coroner are discussing the short cadaver's injuries you can see the little guy breathe between takes.
Revealing mistake: At the start when the camera pans away from the dead body, the "D.B." swallows when he's supposed to be dead.
Revealing mistake: The dead kids head on the blanket in Death Valley keeps changing position between shots.
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.