In this lovely neighborhood you'll have to eliminate Vinnie Sinitra, a snitch who is under witness protection program. The area is crawling with agents, so you'll have to be careful.
Approach the catering van and use the sedative on the donuts in there (ha ha!). The waiter will take them to the second van, which turns out to be secret agents' comm central. When they're fast asleep, enter their car and take the suit from one of them. You now have access to the whole map.
Go to the back of the house to see the victim's wife taking a bath. She has a microfilm in her necklace, and you're here to get it back. When she leaves the pool, follow her and sedate her near the sauna (no one should see that naturally). Take the microfilm (a shame you can't wear her clothes, huh) and place the body inside the sauna.
* - Vinnie's TV.
You now have to take care of Vinnie. Leave the house and mess up with the power box near the entrance. Go to the TV Room, marked above. Vinnie will send his personal bodyguard to see what's wrong with the TV, and you'll be with him alone. That's your chance - kill him quickly and leave the house. Change back to your original clothes and scram.