Last year's failed Democratic nominee told USA Today newspaper that there "certainly was an understanding of some sort" -- and direct communication -- between Trump's campaign officials or associates and Russia.
"There's no doubt in my mind that there are a tangle of financial relationships between Trump and his operation with Russian money," she said in the interview published hours before she kicked off her first book-signing for the memoir, "What Happened."
"And there's no doubt in my mind that the Trump campaign and other associates have worked really hard to hide their connections with Russians."
The Trump campaign's links to Russia are under investigation by special counsel Robert Mueller and by multiple congressional committees.
Clinton's assertions in several interviews coinciding with the book launch amplify a core message of her campaign confessional: that a series of external forces conspired to prevent her from becoming the nation's first woman president.
"There were all of these outside forces coming at me right until the very end," she told National Public Radio.
Comey and Sanders
Among them: the FBI's relentless investigation of her emails, and the announcement by then-director James Comey, just 11 days before the election, that the bureau was re-opening its probe into her use of a private account and server while secretary of state.
"After the Comey letter, my momentum was stopped," Clinton told NPR.
"My numbers dropped, and we were scrambling to try to put it back together, and we ran out of time."
Clinton also lashed out at her progressive rival Bernie Sanders, whom she felt refused to fully back her general election campaign.
"I didn't get anything like that respect from Sanders and his supporters. And it hurt," she told Pod Save America, an internet podcast.
Clinton might be finished as a presidential candidate following her November loss, but she is not going away quietly.
Her 15-stop book tour is intended not only to drum up sales but perhaps burnish Clinton's standing as a prominent figure in US political life.
But the former first lady and political survivor, who in a quarter century in public life rarely gave Americans a personal peek behind her professional veneer, shows a vulnerable side in her book as she describes her post-campaign funk.
She admits that not a day goes that she doesn't think about why she lost, and "the aching sense that I let everyone down."
"It's going to be painful for quite a while," Clinton writes.
"But I'm not going to sulk or disappear. I'm going to do everything I can to support strong Democratic candidates everywhere."
She does not hold back in her criticism of Trump, branding her billionaire nemesis as an incompetent, unworthy, sexist "liar" in her book.
Clinton offers a personal reckoning of her election loss: how she was expecting an easy victory but was "shell-shocked" on election night; how she refused antidepressants and therapy, but drank her fair share of "Chardonnay;" and how she sought refuge in her family.
But the prospect of the twice-defeated Clinton -- first by Barack Obama in the 2008 Democratic primaries, then to Trump last year -- very publicly foisting her suggestions on how to move the political debate forward has made some Democrats uncomfortable.
Despite some nudging by those in her party to exit the stage, Clinton makes clear she is keen to conduct an autopsy on the 2016 election.
"People are tired. Some are traumatized" and others want to keep the focus on the investigation into Russia's election interference," she writes.
"I get all that. But it's important that we understand what really happened," she adds. "Because that's the only way we can stop it from happening again."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)