hmm, i'd suggest you have check points everywhere on your stage, since the bad guy does not know exactly where your man is (unless he has a radar which would just make your programming life hell), he moves from checkpoint to checkpoint, you then use the "get static line of sight command" to check if as he moves he can see you man (no walls blocking view), if he does then he pursues. If the bad guy pursuies and hits a wall (meaning that you have outran him) he then continues his checkpoint to checkpoint journey.
to make it even harder, the bad guy is very fast so once he sees you, he's gonna always follow unless you program your ai to kill slowly, then he attacks for a while then runs away again like in unreal tournament.
you set the checkpoints in a way that the bad guy can move from one to another withough hitting a wall. Then you use the "point object" command to point to the checkpoint and "move object" to move there. when he gets there, he chooses a new one etc. So basically, for example you have 5 checkpoints (all with x and y coordinates), your badguy moves from 1 to 2 to 3 to 4 to 5 to 4 to 3 to 2 to 1 etc and all the while checks to see if he can see the good guy.
if u understood that then i'm sure u could find more complex paths for you a.i to follow.
your birth was a blessing, sent to live and die on earth as a lesson, we each have a star all you have to do is find it, once you do, everyone who sees it will be blinded - DMX