Being blamed for equipment loss. I did not lose it. How do I proceed?

My dad bought my sister and I a capo to use for my 4 string banjo and her ukulele. I used the capo a couple months ago and after I put it back in my case. A couple months after that my dad starts talking about how the capo is gone and my whole family blames me for it since I was the last person who had it. I did NOT lose it, I put it back in my case so someone must have taken it out. Everyone else denies removing it. My parents are threatening to make me buy another capo and my sister is acting like the victim when she barely used it. I've looked EVERYWHERE and can't find this capo including in my case which was the last place I left it. How do I proceed?