A Missouri Highway Patrol car was involved in a crash as the officer was on the scene of another accident. At 11:40 a.m. Saturday on Interstate 55, one mile south of Marston, a Patrol car driven by Conrad L. Purnell, 28, of Poplar Bluff, was parked with its emergency lights activated, according to the Missouri State Highway Patrol's report. Purnell's car was struck in the rear by a northbound vehicle driven by Stanley A. Partin, 57, of Portageville.