Ahly chairman Hassan Hamdy was released on a LE2 million bail on Tuesday after being questioned by Egypt's Illicit Gains Authority (IGA) on charges of illegally accumulating wealth.
According to state-run news agency MENA, Hamdy has failed to explain how he had accumulated around LE500 million during his time as the chairman of Al-Ahram's advertising agency.
He had his assets frozen by the IGA, MENA added.
Hamdy has recently come in for fierce criticism by Ahly's hardcore supporters (Ultras Ahlawy), who hurled a barrage of accusations against the 63-year-old, who has been the club's chairman since iconic president Saleh Selim died in 2002.
They called on him to resign from his post, saying he had not done enough to pressure Egyptian authorities into punishing the culprits of February's Port Said tragedy, which left over 70 fans killed in the country's worst-ever football disaster.
They also deem him as "part of the dismantled regime", accusing him of fraud.
"We said before that Hamdy should leave because he conspired with the Egyptian Football Association over the Port Said case," Ultras Ahlawy said in a statement on their Facebook page.
"And now that things have become clear for many people, we will not allow Hamdy to tarnish the image of our club. You have run out of credit, you have no option but to depart."
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