Tell you what, there is no way to find enough evidence to idenfiy who forged the document. The only evidence is the signature, which can be signed by another stranger, or use foot to sign it.
I sincerely advice you guys don't put too much trust in this U.S. law system, unless you are rich enough, unless you are not inadmissible to U.S.. How can a foreiger file a lawsuit when she/he is banned from entering U.S.?
The ultimate solution is to improve the law and allow the employer to withdraw his cancellation freely.
