My clients site was penalized due to link exchange. I was put to blame because he said I was the only one who's working on it.. The only work I have done was creating blog but not linking to the clients websites. Articles are unique, written manually.. Bottomline.. I didn't use any software neither do the link exchange. I have a doubt that my client is lying. I just want to know how to verified it based on the things that I have done. I'm not sure if this is possible. Will pm you the clients site details. Thanks in Advance.