if you lost your bitcoin you cannot do any thing because it you cannot even claim your bitcoins in police station.
Unfortunately,right and thats the only drawback using a virtual currency as every thing about it is online,you cannot complain about it anywhere,even if you send bitcoin to some one else by mistake,but due to anonymous transactions,you cannot know who is owner of that address.So you cannot recover back your lost bitcoins.
yes being anonymous characteristic you even do not know that who is really own the wallet who has stolen your bitcoins.