Former Geelong Football Club sponsor Sy Giang Nguyen has been hit with more than 300 charges by police over an alleged multimillion-dollar fraud.

Victoria Police said on Thursday the 59-year-old had been charged with 309 counts of obtaining financial advantage by deception over a five-year period by targeting the Geelong-based disability service provider, genU, to obtain more than $10 million.

Police said their long-running investigation began in February 2023 after they “identified suspicious activity relating to accounts being wrongfully charged to the organisation”.

The former information technology manager once rubbed shoulders with some of the nation’s most prominent sporting and corporate figures, and set a Guinness World Record for drinking the world’s most expensive cocktail.

The 59-year-old was once a generous benefactor of the Cats and a friend to some of Geelong’s greatest players. He had access to a private villa at Crown Casino for almost 20 years, and ingratiated himself with some of the nation’s most prominent corporate figures.

In Melbourne, his home base at Crown included sprawling living areas replete with a baby grand piano and a stripper’s pole, a 12-person dining table, private bar and on-call butler. Nguyen’s towels and robe were all embossed with his initials.

In 2015, Nguyen consumed a $12,500 drink known as “The Winston” – made with 1858-vintage Croizet Cuvee Leonie cognac – at Crown’s former venue, Club 23.

Despite his gilded lifestyle, Nguyen was paid an average salary for his role as an IT manager at genU – one of the nation’s largest not-for-profit providers for the National Disability Insurance Scheme. He was previously employed in a similar role with the St Laurence Community Services, since the 1990s.

In 2022, Nguyen was dismissed by genU.

In a statement released on Thursday afternoon, genU chief executive Dr Chelsea Tobin said for someone to allegedly target a not-for-profit organisation that provides support to vulnerable members of the community was deeply disappointing.

Nguyen and his lawyer, Roger Vrachnas, of Gigliotti Lawyers, declined to comment.

He will appear before the Geelong Magistrates’ Court on August 25 in relation to the 309 criminal charges.