The sons of a Qatari prince who died nearly 12 years ago have filed a lawsuit against the Swiss-based HSBC Private Bank for damages worth billions of dollars because of the bank’s alleged refusal to give them access to their father’s account, a Saudi newspaper reported on Sunday.

Late Sheikh Khalifa bin Ali bin Abdullah Al Thani, a member of the ruling family, is believed to have deposits of more than two billion euros ($2.6 billion) with HSBC Private Bank, part of the London-based giant HSBC Group, the Arabic language daily Aleqtisadia said, quoting legal sources.

The paper said it had seen a copy of the suit filed by Sheikh Khalifa’s heirs against that bank, which they accuse of “persistently refusing” to give them access to their father’s account since he died in 2000.

“The lawsuit is expected to aggravate HSBC’s existing financial problems, which has nearly 3,200 employees and manages around 117 billion Swiss francs ($126 billion. There are reports that the bank is expected to let fo of its CEO Alexandre Zeller,” the paper said.

“According to the sources, there are banks that have more than once concealed funds possessed by wealthy Arabs who died long time ago. One of these cases involved late Lebanese businessman Abu Qassim Hamoud whose wife claimed that just before his death that he had deposited nearly $50 million in an account.”

The paper did not name the Qatari Sheikhs involved in the lawsuit nor did it specify where it was filed.