A claim of responsibility has been made by a previously unknown group calling itself the Deccan Mujahideen but this could be a hoax. It seems pretty much accepted that the terrorist came from Pakistan and do not live in India. I guess India has to tighten the immigration to try and prevent terrorist entering in the future.
The sad thing is, they simply using India because they know a lot of tourists got they. Whilst all the victims are innocent, the attacks are not actually aimed at India.