Found my underwear in brothers room

A couple days ago I was vacuuming my brothers room and I found a pair of my panties under his bed which kinda freaked me out

My mind went crazy trying to think of ways they could have gotten there.

Maybe our dog got to them somehow and brought them into his room, but I don’t just leave my clothes lying around so I don’t see how. I had noticed that couple pairs were missing but just assumed they got lost in the laundry or something.

I don’t know what to do now, i’m leaning towards doing nothing and just hope that it was somehow the dog.

My brother is not young, he is 32 years-old this year and I am afraid to think the worse, I am stopping my thoughts as I don’t want to go further down that lane.

I wish it was the dog but I have no idea to find out, I do not have a camera at home neither can the dog speak human language.

What should I do? Should I confront my brother about it or should I tell my parents or should I just keep quiet.

I am scared as my parents are seldom home and if he is really what I think he is, I could be in danger. This kind of thing always start somewhere and I don’t it to get worse.

Please advise me what should I do?