purposely dropped ball

Question
Let's say there's a runner on first with no outs. A line drive is hit to the shortstop and you can tell he purposely dropped it to get a double play. It that legal to purposely drop a line drive in order to get a double play? If it's not is batter out and runner must return to base occupied at time of pitch which would be first?
Thanks

Answer
Heather,
This is called the Infield Fly Rule.  The batter is out and runners can advance at their own risks.  This rule is to prevent what you have described.  Because you were specific to a "line drive" I would also ask this question to an expert umpire because I have never been an umpire and I am not an expert on rules.  

Thank You,
John Priest