Donald Trump insists that we don't know who was behind the cyber attack on the Democratic National Committee. Is he right? Bloomberg Technology's Jordan Robertson talks to Mike Buratowski, who oversaw the investigation into malicious code that spied on emails sent by DNC officials and others. After examining the hints left behind, they tackle the big issue: If hackers backed by Russia really were the perpetrators, what more could they do to mess with Americans' votes and U.S. democracy?