Hillary Clinton took a personal and public interest in the investigation of a Bangladesh-based bank that was owned by a close friend and Clinton Foundation donor while she served as secretary of state.

Mohammad Yunus, renowned Nobel laureate and founder of Grameen Bank, faced friction from the government in his native Bangladesh in 2011 after political opponents accused Yunus of diverting aid money to profitable side businesses.

Emails released by the State Department Wednesday indicate Clinton followed Yunus' plight closely.

She even traveled to Bangladesh in 2012 and met with Yunus before publicly calling on the Bangladeshi government to end its probe.

Yunus' bank pioneered a system of microloans to impoverished individuals — mostly women — that allowed them to start small businesses and lift their families out of poverty. The model spread around the world as an innovative way to foster economic development, although microcredit programs have met with varying degrees of success.

Critics have said the investigation into Grameen Bank for alleged wrongdoing was instigated by Prime Minister Sheikh Hasina for political reasons.

For example, a 2014 article in Foreign Policy Journal recounted rumors from Bangladeshi journalists that Hasina was motivated by anger over Yunus' receipt of the Nobel Peace Prize over herself.

According to the journalists' theory, Hasina was upset that former President Bill Clinton had pulled strings to get Yunus the award.

"Hasina was upset because she believed she — instead of Yunus — deserved the Nobel prize for her role in ending a decades-old tribal insurgency in eastern Bangladesh and that Yunus somehow manipulated the Nobel committee through strong-armed lobbying with help from his American friend, Bill Clinton, former U.S. president," the article said.

Other reports speculated Hasina's aggressive probe was prompted by Yunus' brief flirtation with running for political office, which he ultimately ruled against.

But Grameen Bank drew international attention after a Danish filmmaker alleged Yunus had taken part of $100 million of aid money from the microcredit operation and put it into Grameen Kalyan, an affiliated healthcare nonprofit.

Some reports suggested Yunus had set up dozens of smaller companies to avoid paying Bangladeshi taxes.

Clinton and Melanne Verveer, the ambassador-at-large for global women's issues, communicated directly with Grameen Bank during the government's investigation, new emails show.

Additional emails included in past releases, as well as some obtained through the Freedom of Information Act, paint a picture of the deep concern Clinton held for the probe of Grameen Bank.

An email chain obtained by Citizens United, a conservative watchdog group, shows the Clinton Foundation was also in direct contact with executives at Grameen Bank. In June 2012, a foundation employee forwarded a translated statement from Yunus to Clinton's top aides.

"In case you haven't seen this already, WJC wanted HRC and you to see this," wrote Amitabh Desai, director of foreign policy at the Clinton Foundation, to two of Clinton's top aides. Desai was referring to Clinton and her husband by their initials.

David Bossie, president of Citizens United, suggested Clinton's decision to get involved with the investigation of Grameen Bank was unethical regardless of the circumstances of the probe.

"At the end of the day, you have Secretary Clinton traveling to a foreign country on an official trip urging a foreign government to stop investigating a donor to the Clinton Foundation," Bossie said.

The details of the case are certainly murky, and Clinton was far from the only public figure who ran to Yunus' defense when he came under fire.

Investigators discovered Grameen Bank had spun off a series of subsidiaries using microlending funds in violation of its own charter. Yunus was reportedly ousted from his position after violating Bangladesh's retirement laws.

But some have said the investigation into Grameen Bank was driven primarily by the prime minister's desire to overtake the financial institution and break it up into smaller parts. The New York Times editorial board urged the Bangladeshi government to "stop meddling in the affairs of this important financial institution, which serves 8.4 million rural women" in a 2013 piece.

Other observers criticized the government there for its seemingly baseless accusations against the microlender, some of which led Hasina to strip Yunus of his title.

The Center for Global Development defended Grameen Bank, writing in February 2013 that the Bangladeshi government's investigation offered "no suggestion that Yunus was corrupt, or that any of the alleged illegalities were perpetrated for purposes other than the social good."

Two of Yunus' organizations, Grameen Research and Grameen America, donated to the Clinton Foundation, donor records show. He has been heavily involved with the Clinton Foundation for years.

For example, in March 2013, Bill Clinton announced that the Clinton Foundation and one of Yunus' own charities would team up in Haiti to build "socially responsible forests."

Yunus has frequently attended Clinton Global Initiative events, speaking at a number of the charity's glitzy annual meetings.

Hillary Clinton publicly backed Yunus in May 2012 after meeting with him in his native Bangladesh. She chastised the government for its interference with Grameen Bank.

"We do not want to see any action taken that would in anyway undermine or interfere in the operations of the Grameen Bank or its unique organizational structure where the poor women themselves are the owners," she said.

Her emails indicate she kept tabs on Yunus' situation while serving as secretary of state. Much of the State Department's internal discussions about him and Grameen Bank have since been classified.

In February 2011, the president of the Grameen Foundation sent Verveer an email with the subject line "Latest Grameen Update." The entire email is now classified.

Verveer forwarded the update to Hillary Clinton and informed the former secretary of state that Yunus would be in town the following month for a press conference promoting his work with microfinance, which Verveer herself was slated to attend.

But Yunus ultimately did not make the event because he was not permitted to leave Bangladesh.

"Sorry, I have to cancel my trip to the US," Yunus wrote in March ahead of a planned appearance alongside Clinton at the National Press Club in Washington, D.C. "Situation does not allow me to leave the country. Sorry for the inconveniences."

A sender whose identity was redacted forwarded Verveer an article in December 2010 that laid out allegations against Yunus. The press clipping quoted the prime minister of Bangladesh, who excoriated Yunus for "diverting foreign aid from Grameen Bank to another company."

Verveer passed the exchange up to Clinton the following day, but her thoughts on the article were also classified.

"Just when we thought things had calmed down," Verveer said of the article in another chain.

Clinton asked a different aide to "look into this" for her. "I'd like to know what is really going on," she said.

Attending a ceremony for another charity with close ties to the Clinton Foundation, Yunus remarked to Verveer that it was "wonderful" to meet Bill Clinton.

"I was at the Rockefeller Foundation Award ceremony where Bill Clinton was awarded the life-time achievement award. He gave a very inspiring and insightful speech," Yunus wrote in July 2011. "He elaborately mentioned my relationship with him and his commitment to microcredit since Arkansas days."

Yunus said the former president had a "detailed memory" of his work on microcredit, but the remainder of his message about his relationship to the Clintons was classified.

Lamiya Morshed, executive director at Grameen Bank, sent top State Department staffers a copy of Yunus' resignation letter in May 2011 shortly after it was blasted to the press.

Verveer's comments on the resignation were classified. Clinton remarked in response that Yunus' resignation was "sad indeed."