Q: Trouble signing in.

Nope. You have an expensive paper weight. You probably bought a stolen phone and there is no way to fix it without the original owners apple id and password.

Yes their is a way to get it and tell the previous owner to turn find my iPhone off watch this video

http://m.youtube.com/watch?v=x-sI9uR01XM

Follow the steps in the video and it will allow you to get the previous owners email if they ever used FaceTime on the device if you are lucky it will show the email when you open FaceTime then you can try to contact them and tell them to disable find my iPhone.

No it will not work. He cannot get past the activation so how is he going to do a facetime. Don't post stuff you don't know anything about. Activation lock was made to prevent exactly what you describe.

They don't do FaceTime they bypass the activation and it will only allow you to open FaceTime and get the previous owners email watch the video.

I did watch the video but you can bet that if it is stolen then that guy will be arrested quick. Also I bet apple will fix that problem quickly.

No the video will not help you. It will only give you the original owners email address and if it is stolen you will be out of an iphone either way.

Ya that's true I would take it to apple.