In July 2016, Seth Rich, a young staffer working for the Democrats, was shot in the back in a Washington street at 4am. The police said it was a robbery but nothing was stolen - his watch, phone and wallet were found with him. The murder took place during one of the ugliest and most vicious presidential campaigns in American history. Within weeks of his death, stories emerged that Rich was behind the Wikileaks leak of thousands of damaging internal emails detailing the inner workings of the Democratic National Committee and Hillary Clinton's campaign - and that his murder was no random robbery.

• Documentary