Stalker at a Track Meet?

I'm a high schooler and am on my school track meet. A a recent meet, I was getting ready for a race when a guy from another school randomly came up and started talking to me. I tried to b polite, but for the next 6 hours, he'd follow me and my freind around, trying to talk to us. We tried everything to get rid of him; we hid in the girls bathroom, and he just waited outside. We'd avoid making eye contact or even looking in his drection, but he'd still follow us! When i was warming up for events with my teammate, he'd literally stay about five feet away, no matter where I ran or what I was doing. Again, I'd never seen him in my life, and was not leading him on in any way. His school is at all the same meets as mine, and I'm dreading going to them, because he made it clear he won't be leaving me alone. I don't want to be harsh or rude, but I really need him to go away!!! I can't concetrate on my running when I'm wondering if he's standing behind me! Any ideas?