An off-duty police officer who saw the truck while working at a construction site on Center Street began to pursue the Explorer in his own vehicle. The officer, who has yet to be identified by police, chased the Explorer nearly two miles to Mountainville Road on the south end of the city when the sports utility vehicle, which was driving at an extremely high rate of speed according to witnesses, lost control, went airborne and rolled several times before coming to rest in a driveway.