Abrar's predecessor Abdusalam Omer signed the contract with Shulman Rogers. He resigned in September after a U.N. report said the central bank effectively functioned under his leadership as a "slush fund", with about 80 percent of withdrawals made for private purposes and not for the running of government.
According to the sources familiar with Abrar's allegations, she said she had come under pressure to approve the arrangement with Shulman Rogers after she became governor.
Shulman Rogers and a presidential spokesman said Somali businessman Musa Ganjab had been involved in the search. However, they denied the law firm or the government would pay him for this work or that he would take an improper cut of the recovered funds. Ganjab did not respond to a Reuters request for comment.
According to Abrar, pressure to approve the arrangement came right from the top, including the former foreign minister, Fozia Yusuf Haji Aden, and the president, the sources familiar with her version of events said.
"(This) never happened. I never came across it, I never asked, I never heard it, I only heard after she resigned (about) all these things, not before," Mohamud said.
The sources said the tipping point for Abrar was pressure she says she came under from Aden and other officials to open the Dubai bank account. Saying she believed her safety was at risk, Abrar agreed to co-operate and fly to Dubai to open the account. Instead, when she arrived, she resigned and headed to the United States.
Mohamud denied that an account was to be opened in Dubai, adding that he instructed Shulman Rogers to put recovered assets into a central bank account. The U.S. law firm confirmed this and denied the Dubai account plan had existed.
Reuters requests for an interview with former foreign minister Aden made through the presidency were declined. However, a presidency spokesman said it was "absolutely not true" that Aden, who lost her portfolio in a January cabinet reshuffle, had put pressure on Abrar over the Shulman Rogers contract or the Dubai bank account.
Some diplomats interviewed by Reuters admitted that Western powers were unlikely to hold back aid or military support to Somalia worth hundreds of millions of dollars a year.