<p>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.</p><p>So who is Julius Kivimäki, and could he be the person who held a nation’s darkest secrets to ransom?</p><p>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.</p><p>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.</p><p>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?</p><p>Written and presented by Jenny Kleeman. Producer: Sam Peach. Executive Producer: Georgia Catt. Sound Design: Sam Peach Original music composed, performed and produced by Echo Collective. A BBC Studios Production Commissioning Executive is Tracy Williams Commissioner: Dan Clarke</p>