I got the same e mail and many others like this even fbi E MAILS intimidating me to pay the fees requested. THe problem is (according to what i read on the internet) that these Nigereians arent under any laws specifically target to them for scamming to have them arrested and convicted.
A scam is easily recognizable when they ask for specific personal info such Bank Account number and bank with all your personal info, RED FLAG right there, another is there are no verifiable phone numbers on the address head of letter be it email or regular mail, it isn't mailed thru registered letter also is a big red flag for anything such as contained in these emails and letter