Some convicted criminals released on parole or probation are required to wear electronic monitoring devices so that police officers and court officials can track their movements. Despite these precautions, individuals serving their sentences in the community are still responsible for almost half of the incidents of gun violence prosecuted in the United States, says University of Pennsylvania criminology professor Charles Loeffler. Adding existing technology to current monitoring devices, though, could help deter these shooters by recording and reporting when they fire a gun.