Hi, 863211:
Thanks a lot for your help. I want to ask one more question about who should sign the letter if my friend (a faculty) can help provide an offer. ( He can provide the letter at any time).
You mention the dean or chair need to sign the letter.
1 I have an research associate job (offer signed by PI of the lab) and a research scientist job ( offer signed by Human resourc recruiter). So it is uncommen to ask the Chair sign the letter.
2. My friend told me that to issue a postdoc offer is much simple than a research associate offer. In postdco case, the offer is addressed by postdoc office. In the research associate case, the offer is addressed by the human resource (which will take long time). This is the procedure with different university. How can USCIS require chair sign the letter, is it really mandatory from USCIS side.
3. some lawyer mentioned that PI can sign the employment letter to surrpport Eb1b case ( for a permanent job offer), how do you think?