ransom_man’s final post contained clues to his identity. In those clues, former cybercrime detective Antti Kurittu recognises similarities to of the biggest hacker he ever investigated, a Finnish teenager called Julius Kivimäki.

So who is Julius Kivimäki, and could he be the person who held a nation’s darkest secrets to ransom?

Jenny’s search for answers leads her away from Finland, to meet a man in Illinois named Blair. Blair grew up in the hacking scene, and his time in the same circles as Kivimäki would shape his life forever.

Blair found himself at the centre of a vicious online feud that spilled into the real world. It began with an unexpected takeaway delivery and ultimately put his and his family’s life in danger.

Jenny explores how Julius Kivimäki became a globally notorious hacker - his name has been linked to grounding of a plane with a hoax bomb threat, the targeting of elite universities and multinational corporations, and perpetrating tens of thousands of hacks. But was Vastaamo among them?

Written and presented by Jenny Kleeman.