Hi Kamesh,
As per my knowledge, in one of the organizations, they did a professional reference check, and then they had given him offer letter. When the candidate accepted the offer, they have asked him to produce copies of her previous employment service certificates/experience certificates, educational certificates (like degree certificates, marksheets), professional references, payslips to do a back ground verification.
The offer letter states that, the offer/employment is conditional to a good back ground verification.
So, it is a question, whether the background verification will be done before he joins the company or after he joins the company.
Thanks.