SEO Expert Needed to Troubleshoot Google Penalty

Hi I have a 3 year old website that was ranked very well in Google USA. However around 15th January of this year, it suddenly went overnight from Page 1 to Page 10 and has not recovered since. It continues to rank on 1st page for the same keywords in Google India. I need a SEO Expert to diagnose and fix the the cause for this Google Penalty. Please bid ONLY if you have good SEO experience and have feedback on GAF.