Some of the emails had the subject line, "Think Twice." They were sent from a spoofed email address. The sender claimed to have had an associate plant a small bomb in the recipient's building and said the only way to stop him from setting it off was by making an online payment of $20,000 in bitcoin.
Some people that received the email ended up paying the requested demand. 
( z1 end-up :ARG1 ( z2 person :mod ( z3 some ) :ARG0-of ( z4 receive :ARG1 ( z5 email ) ) ) )