My favourite thing about this entire FML is your name

Did you get your backpack back?

Can you turn him in?

Damn that's awkward sorry op

Virginity after a backpack… I suppose that's perfect revenge in some universe.

That username is hilarious!

He smashed your window, you smashed his daughter's hymen. Let's call it even!

Good! He steals Your backpack, You steal His daughter! An eye for an eye.

There are two possible options here OP. A) Your girlfriend's dad is already aware you are with his little girl and he's stalking you. Although that was the first time you met him, that's not he first time he's met you. He simply stole your backpack because he's insane and has some sort of plan in play. Or it's option B) You don't have to ask your girlfriend's dad what he does for a living... he's a thief. Has it ever occurred to you that your girlfriend may have lured you to him? Did you see that movie Get Out? Dude... GET OUT.

He took the backpack to check if you carry condoms.