The Michigan-based contractor whose workers caused the fatal explosion in Sun Prairie by cutting a gas line isn’t registered to do business in Wisconsin. Its possible V-C Tech doesn’t have to be registered to function as a sub-contractor on jobs like that one. Crews were installing fiber optic cable lines July 10th. Sun Prairie police say they are still considering whether to file criminal charges against any worker involved in causing the explosion and the timetable for making that decision has been pushed back. Sun Prairie firefighter Cory Barr was killed after the leaking gas was sparked and created a huge fireball, destroying seven downtown businesses.