blue light bandit
n.— «After nearly deadlocking Thursday, a Chatham County Superior Court jury returned Friday and delivered a guilty verdict against one of Savannah’s alleged “blue light bandits.” Jimmy Bradford, 20, was sentenced to 15 years in prison on an armed robbery charge stemming from an incident on March 14, 1984, in which robbers used a flashing light and posed as law officers to stop and frisk a motorist.» —“Chatham jury convicts alleged ‘blue light bandit’” by Margaret L. Knox in Savannah Altanta Journal-Constitution (Ga.) Jan. 24, 1986. (source: Double-Tongued Dictionary)