Factual error: Brown and Stokes are investigating a mysterious fatal accident involving a Jeep and a downed power line. They state that the driver would have been safe if the Jeep had made contact with the power line because the tires would have insulated the Jeep from the electrical current. Wrong. First, a car is a Faraday cage, that is an electrical current would pass on the outside of a car on the way to the ground. As long as you don't touch the outer surface, you are safe. Second, tires are (almost always now) steel belted radials and conduct electricity nicely. Lastly, it was an open top Jeep. The power line made contact with the roll bar thereby electrifying the inner surface of the Jeep. The driver is in contact with the inner surface. This is a list, from one year from one utility company, of people that died from contact with power lines. You will see that tires exploded from the contact and some caught fire. http://www.sigalarminc.com/HistoricalNotes.htm.
Factual error: Brown and Stokes mix up enough ballistics gel to make a life-size dummy to test their theory. The entire production (getting a mannequin, making a mold from the mannequin, etc,.) takes place in one shift. Ballistics gel needs to cool in a fridge, or on ice, (32-41°F) overnight. That alone eliminates the possibility that it was done in one shift. http://www.recguns.com/Sources/XD3.html.
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.