"Let's remember that Vladimir Putin thinks she interfered in his election in 2011, and has said as much publicly, and I've heard him talk about it privately," said Michael McFaul, who had stepped down after the 1014 Sochi Winter Olympics.
McFaul said that one of Putin's top motivations was a thirst for vengeance against Clinton.
McFaul was the US ambassador to Russia from 2012 to 2014. On Sunday, he spoke with MSNBC about the reports that the CIA determined that Russian hackers helped advance Donald Trump while bringing Clinton down.
McFaul echoed the concerns as he explained that the hacking fits Russia's modus operandi, and said he supported the recent calls for an investigation into their cyber activities.
McFaul also explained Putin's elation at Trump's triumph.
He said that beyond the foreign policy interests that Trump and Putin share, the Russian President disliked Clinton's tough stance as Secretary of State under the Barack Obama administration.