How is it legal for a landlord to come on your rental property & take something that doesn’t belong to them?

Alexis

Our landlord came up under our stairs of our upstairs apartment & stole a child’s bike that I had for children that I babysit. He claimed he didn’t know it was ours and thought it was abandoned so he was going to add it to his yard sale he is having. He had no permission to do this. It was on our rental property. We are current on rent. How is this legal? I’ve contacted the sheriffs office and they said we needed to contact an attorney. I’m literally baffled at this whole situation!