State Department attorneys admitted Wednesday that they had lost copies of a 2012 email between Jake Sullivan, a top former aide to Hillary Clinton, and an employee of the Clinton Foundation.

The email contained an attachment memo about Greek bonds — a significant detail given the heavy investments Clinton's son-in-law, Marc Mezvinsky, was making in the Greek economic recovery during that same period.

Chelsea Clinton, Mezvinsky's wife, is a board member at the Clinton Foundation. The fact that one of Clinton's closest aides shared insider information about the economic climate in Greece with the foundation — just one year after Mezvinsky and fellow Goldman Sachs alum founded a hedge fund that operated primarily by placing bets on international economic trends — raises questions about the many potential conflicts of interest that could have arisen from the Clintons' web of connections.

The email in question was provided earlier this month to conservative-leaning Citizens United through the Freedom of Information Act. Sent in July 2012 from Sullivan to Amitabh Desai, a Clinton Foundation employee, and Justin Cooper, an aide to Bill Clinton, the message indicates a memo titled "Solidarity Bonds Greece Revised" was attached to the email.

But after a lawyer from Citizens United asked the State Department to provide a copy of the attachment, government attorneys said the agency "does not have" the original email authored by Sullivan.

"Hillary Clinton truly left her mark on the State Department - why do the most important emails always end up missing?" said J.T. Mastranadi, spokesman for Citizens United. "The State Department should explain to the American people why this information is unavailable."

Mezvinsky founded Eaglevale Partners in 2011 with a pair of colleagues from Goldman Sachs, where he spent the early years of his career.

The following year, Mezvinsky reportedly helped drum up investments for a fund dedicated to betting that the Greek bailout would raise the price of bonds.

Investors in the fund included Marc Lasry, CEO of Avenue Capital Group, and Lloyd Blankfein, CEO of Goldman Sachs, according to the Wall Street Journal.

Lasry has donated up to $250,000 to the Clinton Foundation, records show. Goldman Sachs executives, in addition to being foundation donors, have given Hillary Clinton more than $200,000 for her presidential campaign, according to the Center for Responsive Politics.

The California Public Employees Retirement System, known as CalPERS, invested $6.5 million in Eaglevale in May 2012, CalPERS records show.

In Oct. 2013, Bill Clinton spoke at a dinner for Wall Street titans and Greek leadership as hedge funds lined up to bet on the bailout of the Greek financial system.

Investments in Mezvinsky's fund came while Hillary Clinton served as secretary of state. While her discussion of the Greek economic crisis in emails is expected given the nature of her position, the fact that her team shared information about Greek bonds with outsiders raises questions.

In May 2012, two months before Sullivan sent the missing memo to Desai and Cooper, a longtime Clinton confidante outside the State Department sent Hillary Clinton information about the European Union's plans to tackle the Greek crisis.

Sidney Blumenthal, who was on the Clinton Foundation's payroll as an adviser around that time, sent Hillary Clinton a memo about the economic tumult that was classified by the State Department and withheld in full.

Eaglevale's Greek-focused fund ultimately suffered "near-total losses," according to Fox News. It shuttered earlier this year.

Mastrandi, the Citizens United spokesman, said his group has asked the State Department why it claims only to have an emailed reply from Desai, the Clinton Foundation executive, and not the original message Sullivan sent from his "state.gov" address, which included the attachment.