My friend stole my ipod !!! what to do?

ok so its been about 4 days since my ipod has been gone i know my friend took it cause she told me one day she was gonna steal it i didnt believe her but then she did on the field trip and she look me straigt in the eye saying she didnt. her mom called me cause she found out she had a ipod and her mom didnt buy it i wanna choke her so bad i know thats mean but she my freaking bestfreind i cant trust her no more everybody telling me even when i get my ipod bak i should kick her ***. urgh do i ask her why she tooked it and lied and didnt tell me she wanted to borrow it or smakc her in da face