I adopted a Jack Russell. He has become aggressive with me, my other dog and a new puppy. The woman I got him from refuses to take him back. I went to one trainer and she tried to work with him but he wanted to attack her. Can I bring him in?

Yes you can

I'm pretty sure they will take him.

That is sad and unfortunate, but yea you can drop him off, they will take him

It is too sad but I think that you can tell them what happened and they will let you leave the cat.