(Bloomberg) -- Citigroup Inc. says that Mukarram Sattar, one of its most senior employees, was desperately trying to help his unemployed nephew pay off credit card debt owed to the bank in the aftermath of the financial crisis. So he asked his junior colleagues to negotiate a settlement.

A decade later, the incident is at the center of an unfair dismissal lawsuit brought against Citigroup by former head of its treasury and trade solutions operations.

Sattar, who’d worked at Citigroup for nearly four decades, oversaw 15,000 staff in more than 100 countries and organized the transfer of over $3 trillion across the world every day, was fired for gross misconduct in 2013.

Citigroup determined that he improperly used the bank’s internal payment systems between 2008 and 2011 to transfer thousands of pounds from a charity he controlled to pay off two of his nephew’s credit cards and, on another occasion, to meet an urgent cash call. He was also arrested in a U.K. tax probe in 2013.

But at a hearing Wednesday, Sattar’s lawyer tried to set aside a lower court verdict that found in favor of Citigroup. Andrew Hochhauser told the court that Sattar was seriously ill, didn’t fully understand the details of the allegations against him and was not able to fully respond to them.

The former banker was suffering from tremors, poor concentration and memory loss at the time and couldn’t attend his disciplinary hearings at the bank, he said.

Sattar’s six-year ordeal emerged at a separate lawsuit in August where Citigroup was seeking to claw back $1 million from his pension.

But Citigroup’s lawyer, Simon Devonshire, said on Wednesday that Sattar is avoiding the core allegations.

Sattar “seeks to erect an appeal by fine tooth-combing the reasons for cryptic little sentences and by engaging in pernickety critiques, rather than looking at the reasons in the round,” Devonshire said.

In one of the main complaints in its dismissal letter, Citigroup alleged that Sattar tried to use his influence to pay off his nephew’s credit card bill.

In September 2009, Sattar instructed his subordinate Arup Basu to negotiate with the bank’s collections department to reach a discounted settlement figure in order to clear the debts, Devonshire said.

“Please be tough; tell him Ali is still unemployed and to assist us,” Sattar told Basu, according to Citigroup’s court documents.

In his dismissal letter, the bank said it was “concerned” that he asked a member of his team to assist him in resolving the matter, describing it as “a wholly inappropriate use of Citi’s resources.”

Sattar was arrested by the U.K.’s tax authority in July 2013 on suspicion of tax fraud. While a civil investigation is ongoing, the criminal probe was dropped without charges being filed. Six years later no action has been taken by tax authorities, Hochhauser said.

To contact the reporter on this story: Ellen Milligan in London at emilligan11@bloomberg.net

To contact the editor responsible for this story: Anthony Aarons at aaarons@bloomberg.net

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