Washington (CNN) Ten days after the 2012 Benghazi terrorist attacks, the top foreign policy adviser at the Clinton Foundation had a potentially lucrative proposal on which to seek guidance from Hillary Clinton's aides at the State Department.

The email from Amitabh Desai to Cheryl Mills, chief of staff to then-Secretary of State Clinton, describes a pitch by Stella O'Leary, a Democratic donor active in Irish American causes.

O'Leary, according to Desai's email, said Clinton had "firmly instructed" her to set up a not-for-profit organization -- one that qualifies for 501(c)3 status under U.S. tax laws -- called Friends of the Clinton Centre.

In his email, Desai says: "I also asked if the new org could be flexible so that any funding raised could be used in whatever manner WJC" -- the initials of former President Bill Clinton -- "and HRC wish in Ireland and Northern Ireland, and not restricted to support only the current iteration of the Clinton Centre in Enniskillen."

The email is among dozens that have been turned over by the State Department to the conservative advocacy group Citizens United, which has filed several lawsuits seeking documents under the Freedom of Information Act. The group says the documents could help provide information about how they allege Clinton and her aides mixed State Department business with the Clinton Foundation's fundraising efforts.

It's an issue that has dented the image of Clinton's presidential campaign. Clinton's use of a private email server for government business while she ran the State Department has now grown into a controversy and has spawned an FBI investigation.

Desai's email from September 21, 2012, provided to CNN by Citizens United, includes details of how the new organization would be overseen by board members drawn from other parts of the Clinton orbit, including officials from the Clinton Foundation, such as longtime Clinton friend Doug Band.

Citizens United did not provide CNN with an exhaustive inventory of all emails it has recovered from the State Department. It first provided some to The Washington Post, which published a story on Thursday afternoon.

But officials at Citizens United say the emails show discussion of a proposal to establish a "slush fund" for use by the Clintons. The email chain doesn't provide any indication of how Clinton or her aides followed up on the idea.

O'Leary, in a phone interview with CNN, laughed at the idea her proposal would be interpreted as a slush fund. She doesn't specifically remember the details of the email but said she established the 501(c)3 organization with approval from the Clintons. She said it has raised about $55,000 for an international summer school program to bring kids from the Balkans and other conflict zones to Northern Ireland.

It was, O'Leary says, "a good-will effort on my part to honor him for everything he has done in Northern Ireland."

O'Leary suggested that Clinton opponents are using the Clinton name and the email controversy to raise money. The Clintons are "the easiest people around which to make money," she said.

The timing of the email discussion is also notable because at the time, Clinton was wrestling with the beginnings of the controversy over the Benghazi terrorism attacks.

Mills sent Desai's inquiry on to Huma Abedin, another Clinton aide at the State Department, with a comment saying that the proposal was new to Mills.

Abedin, in turn, copied another Clinton aide, Jake Sullivan, noting that Sullivan was in the meeting at which Clinton and O'Leary had discussed the Friends of the Clinton Centre proposal. Abedin adds that Clinton hadn't made any commitments to the O'Leary proposal.

The Clinton Centre is a conference facility built on the site of the 1987 IRA Remembrance Day bombing in Enniskillen, Northern Ireland. President Clinton, who helped broker the Irish peace accords, dedicated the building to peace in Ireland.

New York state corporate records list a group called Friends of the Clinton Centre, registered as a not-for-profit organization in 2013. The address for the organization is that of a New York City personal-injury law firm. O'Leary confirmed that was the organization she founded.

A Clinton campaign spokesman referred questions about the O'Leary proposal to the Clinton Foundation. A person familiar with the matter said the Friends of the Clinton Centre isn't affiliated with the Clinton Foundation.

Another batch of emails from 2012 sent by Abedin detail her efforts to help organize dinners in Ireland during a visit by Hillary Clinton.

The emails sent by Abedin on her State Department email account include discussions about dinners with officials from Teneo, a consulting firm that employed Abedin at the same time she worked for Clinton at the State Department. Abedin had left her official role as a State Department employee but was working as a contractor for both the State Department and Teneo.

The outside consulting work was allowed at the time because Abedin was classified as a special government employee. But the arrangement has drawn controversy and is the subject of investigation by Sen. Chuck Grassley, who says he is concerned it may have violated rules against conflicts of interest.

Teneo was founded by Brand, a longtime Clinton friend who served on the Clinton Foundation board.

"These emails illustrate why there are legitimate concerns about the Department's use of the SGE designation and the blurring of the lines between the official business of the State Department, the private interests of Teneo, and the fundraising interests for various entities under the personal control of Secretary and former President Clinton," Grassley wrote in a letter Wednesday to Abedin.

An attorney for Abedin didn't respond to a request for comment.

Nick Merrill, a Clinton campaign spokesman, rejected the idea that there was anything wrong with Abedin's activities.

"This is someone who has spent nearly two decades in public service, and is widely known for her integrity and tireless work ethic," Merrill said in a statement. "After the birth of her son, she took maternity leave. The IG had questions about the details of her leave, Huma answered. Anything beyond that injected into the public sphere is unfounded and from partisans in Congress with a clear agenda. These emails serve to reinforce that these allegations are baseless. It's not surprising, but it is disappointing."

But David Bossie, president of Citizens United, said, "As a result of federal court orders, Citizens United expects to receive more documents from Hillary Clinton's tenure at the State Department and we look forward to sharing those documents with the American people. It's critical that American's understand how the Clinton machine operated inside the State Department."