Well this mission starts at the GS house roof, you have a chopper, bur if you want go in a car, well the target point is the deadend intersection of the train railroad, where you usually find a chainsaw. your objective is a simple investigation , solving the first crime is just a tutorial, im making the other parts. If You need a screenshot of the Target location :

http://i909.photobucket.com/albums/ac295/phoenixwright93/Court%20Records/screenshot1.png