Grand Theft Auto IV Walkthrough

The building you have to infiltrate is across the street from where you parked your car, and is marked on the map by a yellow dot. Go into the apartment building, and begin climbing up to the very top floor. No one in the building will give you a hard time, even if you're wielding a weapon, so as long as you keep quiet and keep walking, getting to the roof should be a cinch. Once up there, head to the yellow dot on the HUD to begin the final part of this brief mission.

A cutscene will show your target sitting on the couch, watching television. The TV is actually the key to this whole mission. Why? Well, you'll see that the guy is sitting on the couch against a wall, and you can't shoot him through the window from there. However, if you shoot the TV, something might happen. Go ahead and shoot the television set. Your target will then get off the couch and stupidly look outside (how idiotic is this guy?). This gives you a three second (or so) window to shoot him, so once you shoot the TV, quickly get ready to aim at this guy's head or chest, and as soon as you can, pull the trigger. If done properly, the guy will die immediately.

With your target downed, all you now have to do is head back to the ground level and back outside. Even with the loud bang of a sniper rifle, no police should be alerted to what you did as long as you didn't mess with anyone else with the sniper rifle (or start any trouble en route to the building and up to the roof). Once you're outside, Niko will then call up Francis, letting him know that the assassination went off without a hitch. That should get that crooked cop out of your hair for a while.