Threw my dogs poop in an outdoor trashcan, lady ran down the street and thew it at me

This might be in the wrong sub, so I apologize if it is, but here goes: I was out walking my dog today. I always take two plastic bags with me to clean up after him. (He is a very small dog and often doesn't even use one.) Well, today he had to make poo, and I promptly cleaned it up. On the corner of the street, there is a trash can outside a small restaurant. It wasn't out of the way to drop the bagged poo in there, so I did. An old lady came out and told me to go back to the bin and take it out. I told her I won't go inside her trash can, as I don't know what else is in there, nor does she. I kept on walking, only to look back at her following me, yelling at me with the bagged poo in her hand!! She dug it out and started running after me with it, yelling, "Ma'am, this is yours!" repeatedly. I ignored her but started walking as fast as my little dog could. She eventually threw it at me and yelled again, "THIS IS YOURS!" I wasn't going to pick it up after she dug it out of her trash can! I told her I was going to call on her for littering, but really, I'm wondering if I should call for assault, too.
P.S. I will always be carrying his poo home from now on, no matter what.

Have to edit this to add that this was not her personal trash can. It was the restaurant's outdoor trash, and she was a worker there who came after me.