A Medford police detective has been placed on administrative leave after he was caught on video threatening to “blow a hole through your f---ing head” while pulling over a driver who drove the wrong way at a traffic circle. Medford Police Chief Leo Sacco confirmed to Boston.com that the man in the video was Medford Police Detective Stephen Lebert. “He’s a 30-year member of the department and works in our detective division,” Sacco said. “He’s a very effective police officer but last night’s incident that’s on video, at least that portion of the video that I saw, is troubling to...