Downstairs tenant's "stuff" is taking over common areas?

She is also the landlord's MOTHER and he refuses to have anything to do with this dispute. I have conceded the entire laundry room to her (including use of the washer and dryer.) We were unable to use the courtyard all summer because she covered the tables and chairs with junk (still there, hasn't moved in months.) She trashpicks indoor furniture and leaves it outside till it molds, then either I get rid of it or she moves it into the house (she picked up a chair set in June and moved them inside last week.) The basement stairs are blocked by her cardboard delivery boxes because she's too lazy to walk to the trash barrels. Yesterday she stuffed giant rubbermaid containers into the garage blocking the door and all outside tools.

I was nice and asked politely, I was not nice and ripped her out, now I'm almost at the point of taking all her junk and moving it to her yard (we each have a section of yard that is our own.)

They have also broken the gate 5 times in the past year, letting my dog out into the street, endangering my child, and forcing me to make repairs.

I'm at my wits end, how far can I go before she calls the cops?