My oldest son caught our neighbor hitting and spraying our dog through the fence while we are at work. HELP!?

I am buying a camera to mount under the roof. Anyone have a suggestion on cheap security system that is wireless? Looking into the CD35VPW Vandal Proof - Color Dome Camera - Indoor/Outdoor...Our neighbors grandson that lives with her and her daughter pokes at our friendly "trained" black lab. Now our dog barks at them through the fence,and my son caught the grandma spraying him with pepper spray while my husband and I are @ work. Luckily it was windy and she missed his eyes. I gave him a good bath and lots of love. He is an inside dog after we get home, but I am worried she may poison him, or worse...so I am getting the security camera. Just wanted to know what all our rights are as far as taking action are concerned?