I got a client, that he received unnatural link warning from google through webmaster tools before 5 months ago. He lost all of his rankings and needs to retain all of those rankings back again. SEO has done by third part company by monthly for his web site and web site owner asking me to fix this. How can I proceed and where I can begin? I know that, I've to remove those backlinks. So I need to find backlinks that built by previous SEO company. How can I accomplish this? What are the tools we can use to find backlinks? I've received webmaster access and saw there about 400 backlinks. Do I need to remove all those backlinks or need to find more. ? If I remove all of those 400 backlinks in webmaster tools and is it enough to send reconsideration request to google? Any help really appreciated. Thank you.