How can I unlock an iPad 3 with an activation lock with an unknown Apple-ID Bought a a second hand ipad  from a yard sale the person had it set to  new installation. I looked at it before I bought it to make sure it powered up, and I got it home and connected to my laptop to start the process I found I i could not go any further be cause the ipad had been locked by another apple Id. When I went back to show the person they didn't know how that had happrned and they didn't recognize the apple Id and now they wont do anything to help try and reset it nor give back my money  and now i'm stuck with a locked Ipad and no money. What can I do now?
With the iPad powered off, press and hold the Home button, connect the USB cable from PC/Mac to iPad.

Continue holding the Home button until you see the "Connect to iTunes" screen, then release the Home button.

Open up iTunes to see iPad in recovery mode.