Hillary Clinton's campaign manager implied Russia might be behind Donald Trump's campaign.
There are real questions being raised about whether Donald Trump himself is just a puppet for the Kremlin in this race.
"We now need Donald Trump to explain to us the extent to which the hand of the Kremlin is at the core of his own campaign," Robby Mook said in an ABC interview Sunday.
Mook added it was "clear" that Russia was supporting Trump's campaign, citing Trump advisor Lt. Gen. Michael Flynn's appearance on the English-language Russian news channel RT (for Russia Today.)
Additionally, former Trump campaign manager Paul Manafort was accused of assisting a pro-Russia group in Ukraine. Manafort resigned last week.
Mook has called for Trump to explain his Russian ties before.
It's not the first time the Clinton campaign has suggested the Russians were involved in the election.
When the Democratic National Convention's emails were leaked, the campaign blamed Russian hackers. Later, Trump said in a speech, "Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing."
However, the founder of Wikileaks, Juilan Assange, implied a DNC staffer who was shot and killed leaked the emails, not Russia.