My sister has stole my things what should I do?

[Supermum11]

So I recently noticed quite a few of my toys from my childhood round my sisters house which is really bugging me as I didn't say she could have them and they aren't hers so she shouldn't have them unless I gave them to her or her child which I didn't.
I have a daughter who is younger than her child and would have like the option to offer them to her she has taken them from our perents house and it makes me wonder what else she has taken of mine or even my child's stuff as I've left her unattended round my house before I'm really angry about it what should I do? I feel like going round her house searching for everything that was mine it's not like her child needs anymore toys he is so spoilt it's unreal he has everything under the sun!

My SIL did this with DH’s toys. She did it the same day she badgered me on the phone to find out whether we were TTC.

Straight round to PILs house and into the loft, photo messages texted of her DD playing with the toys sent to DH and PILs straight away. She knew exactly what she was doing.

I found it really hurtful and cried. I have never seen my DH so angry, he went white.

It caused a rift, he barely speaks to her now.

To be honest, I think if it happened again I would probably tell her we wanted the stuff back and how hurtful and selfish it was for her to take the things without asking. At least then it would have been out in the open.