The following is a list of all 14 briefcase locations. You get a cash reward 
for picking up each briefcase. They can only be collected once, and disappear 
in future playthroughs once they are collected. You can check "Objective" in 
the pause menu to see how many briefcases you have collected for the level. 
Collection is accumulative; you do not have to collect all briefcase in the 
first playthrough.