One of our websites was copied word for word all 400 pages by someone who used a special program to clone the site. We saw the program in the code.
This was done in early April and soon after that we lost a lot of rank in Google. We just discovered the copied site today. It is mirrorred 100%.
We did change the front page of our site since then to make some differences but since the Penguin update, we still have not recovered. We have also corrected the problems in Webmaster Tools. Will the mirrored site affect our Google rank to a severe degree or are there other issues that are affecting us? What can be done about that mirrored site?