Rafael Diaz is a great racing driver and mechanic. It's not hard to guess that he provides vehicles to Los Muertos. Eliminating him will surely cause decrease of gangsters cruising around the city.
In spare time, Diaz organizes car fights in his seat in the northern part of Los Muertos territory. The place is strongly guarded and mad drivers on the huge arena are deadly dangerous. We suggest you to be careful and avoid indirect attack.
Luckily, our sources informed us about secret passage leading directly to Diaz whereabouts. To use it, get to the Agency supply point: Radio 410 Tower. Then go south toward the racetrack captured by Los Muertos. Soon you'll perceive breaches in the wall of the building which you may use to get inside it. We suggest to turn left and continue a well-trodden path for a while though.
If everything goes right, you should reach the fork of the road. Choose the down path and get to the pipes sticking out the building. One of them will help you to get near Diaz. Jump inside and then go down. Soon you will find yourself on the back of the room where your target is.
Destroy the wall using explosives and kill Diaz ("Firefly" or strong kicks should do the trick). Now you just need to get out the garage. Soon the door to the arena will open and you will see mad enemies. Quickly take one of the cars standing nearby and evacuate through the gate.