email contains:

I write you to inform you that my man hid an explosive device (Hexogen) in the building where your business is located. My mercenary constructed the explosive device under my direction. It has small dimensions and it is hidden very well, it is impossible to destroy the structure of the building by this bomb, but in the case of its detonation there will be many wounded people.
My recruited person is controlling the situation around the building. If he notices any unusual behavior or policemen the bomb will be exploded.
I can withdraw my recruited person if you pay. You send me $20'000 in BTC and the device will not explode, but don't try to deceive me -I assure you that I will withdraw my recruited person solely after 3 confirmations in blockchain network.

It is my btc address : 1Dnw2qJxGFCZdE3PzCaVioBB9zERc7SzRB

You must transfer money by the end of the working day. If the workday is over and people start leaving the building explosive will explode.
This is just a business, if you don’t transfer me the bitcoins and the explosive device explodes, other commercial enterprises will transfer me a lot more, because this is not an isolated case.
To stay anonimous I will not log into this email account. I monitor my wallet every thirty minutes and after receiving the payment I will order my man to leave your district.

If an explosion occurred and the authorities notice this email!
We are not the terrorist society and dont take liability for explosions in other places.