"What I want to know is why they favored President Trump", said Sen. "If the election had been on October 27, I would be your president", she said, while also putting responsibility for her loss on her own actions.
Comey also says Russian Federation is responsible for hacking the Democratic National Committee.
Clinton and many congressional Democrats have claimed that the FBI's unprecedented intervention tipped the balance in a close election and gave Republican Donald Trump a critical last-minute boost.
Democrats repeatedly contrasted Comey's decision to talk about the Clinton email investigation while not disclosing that the FBI had begun secretly investigating in late July whether any Trump associates might be working with Russian officials to meddle with the presidential campaign.
"Today's hearing provided our committee members with a valuable opportunity to ask follow-up questions from the open hearing", they said in a brief statement. Worries about Russian hacks plagued the U.S. presidential election and its aftermath, with United States intelligence agencies accusing Russia of meddling in the race for the White House.
FBI investigators reviewing former Rep. Anthony Weiner's computer in an unrelated case discovered he had thousands of emails from Hillary Clinton's Verizon Blackberry account - which they believed were the missing Clinton emails, Comey told the Senate Judiciary Committee.
Only two days before the election the Federal Bureau of Investigation notified Congress that an examination of the emails on Weiner's computer did not change its determination Clinton should not face charges, but Democrats maintain that by that point the political damage had already been done. He said he felt obliged to inform Congress in October when new Clinton emails were found in an unrelated investigation. Democrats are angry that Comey reopened the email investigation just 11 days before Election Day, then announced about a week later the bureau found no new evidence.
Turkish army, Kurdish militia exchange fire across Syria border
Turkey views the YPG as a terrorist organisation, an extension of Kurdish militants who have waged a three-decadelong insurgency. The Turkish army has claimed it has killed 11 "terrorists" during cross-border clashes with Syrian Kurdish fighters.
Clinton speaking at a Women for Women International event on Tuesday cast blame for her election loss on FBI Director James Comey's ill-timed letter to Congress, "Russian WikiLeaks", and misogyny.
Comey said Wednesday that he welcomes the internal inquiry.
"I think overall he is a straight shooter", she said.
Comey did tell Grassley he had never been an anonymous source of quotes in the media on the investigation of the Clinton and Trump campaigns and that he had never authorized anyone in the FBI to do so. Trump has refused to release his tax returns to the public.
The FBI chief said that in the last presidential elections, the Russians were not able to change the actual vote tally, but one day they might.
Pressed by Chuck Todd about the "Strawman argument" that Comey would have faced criticism no matter his decision, Feinstein replied, "that argument in my view, is baloney".
Breaking that policy would be "really bad", Comey said.