Police placed a Waltham man under arrest after he led them on a chase in Watertown on his scooter. On May 7, at 2:27 p.m., an officer monitoring traffic at the corner of Main and Cross streets saw a Vespa-style scooter going approximately 50 mph, on the wrong side of the road while heading east, said Watertown Police Lt. James O’Connor. The operator, later identified as Neil Ozzy Frajul, 26, of Waltham, was not wearing a helmet, nor was he wearing eye protection. At that point the officer tried to stop the scooter, O’Connor said. “The scooter failed to stop and the rider ended up running the red lights in Watertown Square,” O’Connor said.