The independent review into Akinwumi Adesina, who intends to run for a second term as head of AfDB, comes after immense pressure from Washington. According to the bank's board, the inquiry must finalize its work within four weeks in time for the election of a new head scheduled for August.

"The independent review shall be conducted by a neutral, high-caliber individual with unquestionable experience, high international reputation and integrity," the Ivory Coast-based AfDB said in a statement. It also promised to review its policy on how whistleblowing is handled.

Allegations of multiple abuses

Some AfDB staff have accused Adesina of multiple abuses and breaching the institution's code of ethics. The whistleblowers submitted a 15-page report which alleges that Adesina was involved in embezzlement, awarded contracts to friends and relatives, gave fellow Nigerians senior positions and promoted people suspected of fraud.

An internal inquiry recently cleared the 60-year-old Adesina of wrongdoing. In Nigeria, the AfDB's biggest shareholder, many view him as a man of integrity. Nigeria's President Muhammadu Buhari assured Adesina that the country will stand "solidly behind him" as he seeks to stay on as head of the multi-lender.

"His performance in terms of credit analysis and the capacity of member countries to take on certain debt raises some questions," Alufa Bokpin, an economist based at the University of Ghana, told DW. Bokpin however said he would not discount Adesina's first term as AfDB chief.

Adesina's record at AfDB

The AfDB raised $115 billion (€105 billion) in fresh capital in October, in what many saw as a personal success for Adesina. The financial institution remains the only one in Africa with a Triple-A credit rating.

"There have been some internal concerns from the whistleblowers point of view and the fact that the way it was handled, hasn't gone down well with other shareholders," Bokpin said. According to the Ghanaian economist, the allegations Adesina faces could have been influenced by developments surrounding the COVID-19 pandemic. "Countries are looking more inward, there is a rise in regionalism for which the continent would want to hold to its own," Bokpin said.

"It would be difficult to say that the African Development Bank in the last couple of years has done so well, and yet the president has been hugely incompetent."

US unsatisfied with internal probe

The United States, the bank's second largest shareholder, voiced reservations about the internal inquiry which did not find Adesina guilty. Instead, Washington insisted on an independent probe. Several other Western shareholders of the bank have backed the US, whereas Nigeria and other African shareholders have thrown their weight behind Adesina.

For Bokpin, the US has a right to call for an independent inquiry. "The US has signaled clearly that the internal mechanism that the bank followed has not been satisfactory," Bokpin said. "The solution is not to kick out the US but to be more transparent."

At a recent meeting with Buhari, Adesina said the US call for an independent investigation goes against the bank's rules. He has repeatedly described the allegations as a motive to taint his name and that of AfDB.

Nigerians stick with Adesina

Between 2010-2015, Adesina served as Nigeria's Minister of Agriculture and Rural Development. During that time, he was one of the most respected ministers in government. "He has these five focal points that he brought into the organization which focus on human development, agricultural development, rural development and things that can actually accelerate the development of Africa," Waidi Adebayo Gbenro, a research associate at the Centre for Economic and Policy Research at the Covenant University, Ota in Nigeria, told DW. Gbenro said he would like to give Adesina the benefit of the doubt.

Many in Nigeria say as president of the African Development Bank, Adesina also impacted lives in his home country Nigeria. One resident in Lagos told DW: "During his first tenure, he was able to inject funds into Nigerian electricity. A lot of it was for rural electricity and this went a lot to bring about development in rural areas."

"The ethical committee of the board of directors is currently carrying out a review process. We should allow them to do their work without fear or favor so that at the end of the day, we are sure whether the bank's ethics was breached or not," Bokpin concluded.   

Sam Olukoya in Lagos contributed to this article.