I only have a few "friends" on Facebook, in fact I dislike the site. Lately, on junk mail, I keep receiving mails allegedly from my "friends" which are spam, always with a link to a suspicious site, of course I have deleted them instantly. Why is this happening? The email addresses are not those of my "friends", contacted a couple asking if they had been hacked? They new nothing about this.
It's fairly typical for the recipient of an email virus not to know about it until their friends ask them about the weird emails, so I'm guessing this is a virus that one of your contacts has copped and the 'facebook' reference is just window dressing to try and get you to open it.
After you have deleted the emails make sure you also delete your deleted emails folder.
I think this is happening because of virus problem in your friend's system because many times, not only in the Facebook but in many other messengers, user get spam email.