Blood Drops - S1-E7
Factual error: The show falls into the Hollywood myth on polygraphs. Jesse is given a polygraph test after pleading guilty to the 4 murders. He answers all questions, except the last one, honestly. The 4 traces on the polygraph show no real movement on these questions. On the final question, Jesse lies and all 4 traces spike. If polygraphs actually did that, they would be admissible in court. But the reality is, it is the opinion of a highly trained operator that decides if there is a lie. The average person could not look at a polygraph results and point out a lie. There is no huge, visible spike. The producers could have replaced the 4 traces with a red\green light: Green is an honest answer and red a lie.
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.