Why Russian hackers, not a lone wolf, were likely behind the DNC breach

Proving who pulled off a cyber attack is never easy and sometimes impossible. That's the reality investigators face as they try to figure out who breached the network of the Democratic National Committee, which revealed last week that hackers had made off with confidential documents including research on Republican presidential opponent Donald Trump. Russia was fingered as the likely suspect, until a hacker calling himself Guccifer 2.0 stepped up and claimed that he acted alone. But despite what...