My heart goes out to Ms. Sierra's family and friends. This is so senseless.
On where she was reportedly found:
Very, very odd.
The general area is a short walking distance (3-4 km) from Galata Bridge. She was last seen on video walking on the bridge in the direction of Eminonu Pier. Upon reaching the pier she would have been in the major tourist quarters of Istanbul (Sultanahmet, etc.).
The general area the body was found is literally steps from a huge hospital, dozens of huge tourist hotels (the Four Seasons, for example), restaurants, and attractions (Hagia Sofia and the major mosques, museums, etc.). BUT the areas around the walls can be a bit more isolated.
The ancient city walls are tourist attractions in themselves -- some people come to Istanbul solely to walk along their trajectory. In places they are huge masonry edifices with sheer drop-offs.
On the peninsula where the body was found, you have the famous Topkapi Palace sprawled over the top of the hill surrounded by gardens down to the city walls. Then the drop-off off the walls, and a no-man's land of brush, then train tracks, a major roadway, then the Sea of Marmara.
Even though it's steps from an area with no violent crime to speak of, it is an isolated spot someone could be lured -- or a spot that by road would be easy to get in and out of at night by car with no one watching...
Again, I'm deeply disturbed by this outcome. It is just tragic.