Simple, but time-consuming.<br/><br/>The Spoiler was able to trace Whiplash by jumping back to the time of their original battle, and through careful focus, dilating time so as to track the speedster back to whence he'd came.  The young hero had the sense to change clothes away from home so he wouldn't be traced directly back to his apartment, but he obviously hadn't expected time-traveling scrutiny.<br/><br/>With the address, the next part was easy.  Whiplash was Brian McKay, a young artist with an associate's degree from Empire University.  He was actually pretty good, and had sold a couple of paintings, but so far he was still eating a lot of ramen.<br/><br/>It was trickier to figure out when and how he'd gained his speed, but fortunately, McKay had a habit of doing domestic tasks at super-speed when no one was around, and that made it easy to spot-check time periods.  The Spoiler eventually pinned down the time when he'd started that habit at sometime during Brian's junior year of high school...when his family found it odd that he'd quit the track team.<br/><br/>Waiting in hiding at the school's track, the Spoiler finally narrowed down the fateful day...where he saw the portly track coach smirk, as he quietly emptied a mysterious vial of faintly glowing liquid into a Gatorade bottle.  "C'mon, McKay, hustle!" he shouted at the teenager, apparently the best runner on the team until he inexplicably quit.  "We're gonna take state this year for sure!"