Nigerian scammers almost always forge headers on these emails. We found one that embedded this in their email headers: Reply to firstname.lastname@example.org
Mugi or Mugu is what they call a stooge, a mark, the indended victim of these scams.
Id of course, they are engaged in identity theft. You send them your ID and they will use it to assume and scam in your name or the will obtain credit in your name.