There are some scam emails going around asking for large amounts of money from readers, such as $30,000.
The emails contain the following in the subject and in the first line of the email:
BE MORE CAREFUL
The rest of it has a long story saying they’ve been asked to kill you and in exchange for money they won’t. It’s a scam hoping to lure worried people with plenty of cash, and if you’re worried you can mention it to your local police.
Note: this is also classified as a hoax though it’s more like a scam. A hoax is doesn’t involve asking for money whereas a scam does.