Use your sniper rifle when you can see them from afar. If your health gets low, you can sleep on the bed. Location: Alderney, Westdyke. You will not lose much health when you land. Parked west of a building that says Mammon Heights, facing north. No cars can get to you on the train tracks and the helicopters cannot shoot accurately enough to hit you at motorcycle speed.
It can be found in the "Three Leaf Clover" mission.
The block it is on has an alley on the map that goes from east to south. This is the same location you went for the "Bleed Out" story mission. He moves south towards the old hospital.
Before the curve is where the Intruder is parked. At the third road that goes west, turn left. While stopped in a vehicle in a large traffic jam, tap out the rhythm of the musical phrase "Shave and a haircut" with your horn. Use the stairs to your right to give chase.
You will see a response from "The Truth", or his online username "Trooth". Each has two men in them.
Any previously spawned vehicles will disappear. Note: This phone number translates to "WET". Take the Turismo, and drive it to Stevie's car shop.