How do i get my pport back that has been confied at a bar?

my friend used my pport to get in a bar and the bouncer took it away because it wasn't hers. I contacted the bar and they said that it has already been transferred to an agency so what do I do now to get it back?? and what does the agency do with my pport? are they going to turn it into police? i really want to know what it will take me to get the pport back.