I agree. To me, it seems like Renner was too quick to dismiss him too. Of the known characters, I can see why LE zoomed in on him. Maura's scent ended right in front of his house. He claimed to have seen her running miles up the road--- far from his house where her scent ended. To LE, it must have seemed like this guy was trying to distance her from his house and maybe trying to insert himself in the case to get info from them. Also, there was a newspaper article on a psychic who felt Maura was buried in a construction site (he is a contractor). Shortly after this article was published, he came forward about seeing her running up the road the night of her car crash. He reported this a couple of months after she went missing. He claimed that he got the days mixed up, but after looking at his work records, he realized he did see someone running up the road on the day Maura disappeared. There is no proof he saw the article, but it seems a little suspect to me or an odd coincidence.
He could very well be innocent, but his actions seem suspicious.