REWARDS - Respect
Get in a car and make sure Dogg gets in as well. Head to the yellow blip on the radar, to find out that Loc is getting interviewed. As soon as Loc sees you and Dogg, he gets in a hovercraft and speeds away. Dogg and you get into separate ones to chase him. You can't catch him, so make sure to just stay on his tail.
Once he gets on the pier, he switches to a go kart. Again, you can't catch him, so concentrate on driving and keep on his tail. All you have to do is follow him until a cutscene occurs, which will bring you through to the end of the mission.