Breh, they admit in this very same article, they have no evidence.
The CIA presentation to senators about Russia’s intentions fell short of a formal U.S. assessment produced by all 17 intelligence agencies. A senior U.S. official said there were minor disagreements among intelligence officials about the agency’s assessment, in part because some questions remain unanswered.
For example, intelligence agencies do not have specific intelligence showing officials in the Kremlin “directing” the identified individuals to pass the Democratic emails to WikiLeaks, a second senior U.S. official said. Those actors, according to the official, were “one step” removed from the Russian government, rather than government employees. Moscow has in the past used middlemen to participate in sensitive intelligence operations so it has plausible deniability.