Hillary Clinton may have been tipped off about a tough question on the death penalty, which was asked during the US Democratic presidential primary.

As disclosed in a WikiLeaks trove of emails relating to Clinton campaign Chairman John Podesta, the Clinton campaign received word from then-CNN contributor Donna Brazile that a death-penalty question was on tap for the event, which took place at Ohio State University. A man named Ricky Jackson, who was exonerated after being sentenced to death, pressed the candidate on her support for the ultimate punishment.

"From time to time I get the questions in advance," wrote Brazile in the pre-town-hall email. At the time, Brazile was vice chair of the Democratic National Committee in addition to being a CNN contributor. She stopped being a contributor in mid-summer, when she started serving as interim DNC chair.

RICK WILKING/REUTERS Donald Trump has been a vocal critic of Hillary Clinton throughout the election cycle, even coining the nickname "Crooked Hillary".

CNN has insisted that it did not lose custody of the question; reports have suggested that the leak came from Brazile through TVOne, whose Roland Martin co-hosted the debate in cooperation with CNN.

READ MORE:

* Early voting signs positive for Clinton

* Hacked emails shed light on campaign anxiety

* Hillary stays mum on private email server

* Why Trump v Clinton is the best TV ever

Jake Tapper of CNN was a moderator of a March 13 Democratic town hall event in which Hillary Clinton appears to have gotten an unfair advantage.

"To find out that someone was unethically helping the Clinton campaign - tipping them off - is just very, very upsetting," Tapper said in a WMAL radio interview.

"I have tremendous regard for Donna Brazile; she's a good person and a nice person and I like her a lot. But . . . whatever took place here, and I know that I had nothing to do with it. And I know that CNN - we were so closely guarding our documents, they weren't ever emailed around.

2. ...I'm not happy about being hacked by the Russians in their quest to throw the election to Donald Trump. — John Podesta (@johnpodesta) October 7, 2016

"I think this was a follow-up question that Roland Martin was going to ask, theoretically . . . We wanted to put [Clinton] in a tough situation: You support the death penalty, here's someone who was almost killed because of the death penalty - what do you have to say to him?"

Tapper said his understanding was that the question got to Brazile via Martin or someone in his orbit.

Whatever the particulars, it's incontrovertible that the more organisations that are involved in producing an event, the greater the chances that a leak will occur. "I am sure it will have an impact on partnering with this organisation in the future. And I'm sure that it will have an effect on - Donna Brazile is no longer with CNN because she's head of the DNC right now, but I'm sure it will have an impact on Donna Brazile."

One more: It should have an impact on CNN itself, which thinks nothing of larding its payroll with political activists whose first loyalties extend to their allies, and not so much to some news organisation.

LEAKS REVEAL NEW SIDE OF CLINTON CAMPAIGN

WikiLeaks started leaking emails from Clinton campaign chairman John Podesta around October 7.

It's revealed anxiety in the Clinton camp, and offered insights into her behind-closed-doors speech transcripts that she has refused to release.

Hillary Clinton's paid closed-door speeches to Wall Street banks apparently included her dreams of "open trade and open borders" and a suggestion that bankers are best positioned to know how the industry should be regulated, according to the emails.

NEW: @johnpodesta statement in response to @WSJ report that FBI believes Russians responsible for hack of his emails pic.twitter.com/rklB3hVXFS — Brian Fallon (@brianefallon) October 12, 2016

@brianefallon Yes. It tells you that we are an award winning media organization and not 'hackers'. We don't "target" anything. — WikiLeaks (@wikileaks) October 11, 2016

Clinton, who was paid more than US$20 million for speeches between 2013 and 2015, had said she would "look into" releasing the transcripts of the speeches - but she never has indicated any plans to do so. While Clinton has attacked Donald Trump for refusing to release his tax returns, some critics have pointed to the speeches by Clinton as evidence that she, too, has not been fully transparent with voters.

One possible vulnerability identified in the emails was a 2014 speech to Deutsche Bank in which she gave remarks that a Clinton staffer characterised as suggesting, "Wall Street Insiders are what is needed to fix Wall Street."

3. Don't have time to figure out which docs are real and which are faked... — John Podesta (@johnpodesta) October 7, 2016

"How do you get to the golden key, how do we figure out what works?" the email indicates that Clinton said in the speech, speaking of Wall Street regulation. "And the people that know the industry better than anybody are the people who work in the industry." Records show Clinton was paid US$260,000 to address Deutsche Bank in 2014.

In another speech to Goldman Sachs in Arizona in 2013, Clinton fretted that "part of the problem with the political situation, too, is that there is such a bias against people who have led successful and/or complicated lives." She was paid US$225,000 for the Arizona speech, records show.

The campaign staffer cited other worrisome passages that touted Clinton's relationship to Wall Street, including an acknowledgment that she needed Wall Street's financial support.

The emails appear to have been hacked from Podesta's Gmail account and appear to span almost a decade. According to a WikiLeaks tweet, the release represented the first 2050 documents of 50,000 it has hacked from Podesta.