A casino in Las Vegas. You are to eliminate three targets. Despite quite a lot of security, this level is fairly easy, provided you know what you're doing.
Go inside the building, to the main hall, and call the left elevator. Go up the hatch in it and wait until your first victim enters it. When the man is inside, use the fiber wire to choke him. Take his keycard and grab his suitcase. Get back to the ground floor and go to the second elevator.
Wait until Hendrik Schmutz, your second target, enters the elevator and repeat the whole process. Wear his clothes and take his keycard. Leave the Payment Briefcase and your guns in here as well - you'll get back for everything when leaving the level.
Go to the 7th Floor and enter Room 707 to take the DNA Briefcase. Now to the 8th Floor, where you have to enter Room 803. To distract the guards, set off the fire alarm (screenshot above). Once you're inside, use the phone from the table, and your final target will leave the casino area and make himself easy to assassinate.
Quickly go to the casino at the ground floor, still carrying the DNA Briefcase. Get to your target (don't go through the main floor of the casino, there are security cameras). You should manage to get there in time and kill the man when he's still alone in the staircase. If you're too late, though, just meet him in person. He'll think that you're Schmutz and call of his guard. Take the opportunity to strangle him quickly and leave the area. The exit is at the casino level (check the map). Remember to get your things from the elevator.