MEXICO CITY (Reuters) - Manuel Medina Mora, one of the most influential Mexican bankers to work on Wall Street during a long career at Citigroup Inc C.N, has died, the bank's Mexican unit Citibanamex said on Wednesday. He was 69.

Citibanamex said Medina Mora died of amyotrophic lateral sclerosis, a form of motor neuron disease. Earlier, the bank had said multiple sclerosis was the cause of death.

Medina Mora was a powerful executive at what became Citi’s most important foreign unit, credited with turning a laggard Mexican lender into a lifeboat for the large U.S. bank as it rebounded from the 2007-2009 financial crisis.

However, money laundering and loan fraud scandals at the Mexican unit tarnished his legacy, even as he managed to keep a hold on power and run the bank at arm’s length from New York.

Citi bought the lender, known as Banamex, in 2001 and the unit came to account for about 15% of the parent company’s global consumer revenue by 2016, when Medina Mora resigned.

Medina Mora was the third generation in his family to work at Banamex, according to prominent businessman Alfredo Harp Helu, and had the nickname “Mr. Mexico” within Citigroup. In 2016, the Mexican subsidiary was renamed Citibanamex.

Citigroup Chief Executive Officer Mike Corbat paid tribute to Medina Mora, saying he had been a “mentor to many” and helped turn the business into one global franchise.

“Manuel was a pillar of Mexico’s business community yet his impact extended well beyond his home country,” Corbat said in a statement, expressing his sadness at Medina Mora’s passing.

Seen as an effective manager who smartly navigated internal affairs, Medina Mora was described by powerbrokers who knew him as a brilliant and respected banker. Under his leadership, Banamex, one of the oldest Mexican banks in continuous operation, became Mexico’s second-largest bank with more than $26 billion in deposits and over 1,000 branches.

However, a series of scandals damaged his reputation, leading to a significant pay cut in 2014, and likely contributed to his retirement in 2016.

In 2014, loans made to a Mexican company backed by bogus work orders from state oil firm Petroleos Mexicanos [PEMX.UL], or Pemex, cost Citi more than $500 million. In addition, anti-money laundering issues and soured loans created hundreds of millions of dollars in losses.

Medina Mora started as an intern at the bank in 1971, working his way up to lead the privatization of Banamex in 1991. He became chief executive of the resulting Banamex-Accival Financial Group in 1996, before eventually running Citi in Latin America in 2004 and heading its global consumer banking business in 2010.