A federal law enforcement official says it isnât hard to illegally convert a handgun into a fully automatic weapon like the one a 16-year-old Madison boy allegedly used to spray bullets near a busy stretch of road in Sun Prairie earlier this month. Yeshua Schworck was formally charged with attempted first-degree homicide Monday in the Dec. 9 shooting that hit four vehicles, including three that were occupied, around 6:40 p.m. near a BP gas station on West Main Street, the cityâs main thoroughfare. The driver of the Mitsubishi SUV Schworck was riding in when he allegedly fired the shots, Trentin G. Holsten, 19, of Necedah, is charged as a party to the crime.