How can i get my stolen ipod touch back????!!!!!!?

ok so i was at my house. i had 2 friends over. me and my brother were playing our guitars. and my friend dustin was sitting on my bed. then the other friend sheldon, was standing by my dresser where my ipod was. about an hour later i wanted to listen to music on my ipod. so i looked for it everywhere. and i couldn't find it. so i new that sheldon took it because he's known for stealing stuff. anyways how can i get it back. PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!…