Investigators will probe “irregular financial transfers” reported by Sonangol’s new management, prosecutors said in a statement.
Sonangol’s new chief executive Carlos Saturnino angrily criticised the financial management of his predecessor Isabel during a results briefing on Wednesday.
“We started in our roles on November 16, 2017, and tonight we note that the former finance director ordered the transfer of $38 million (28 million euros) to a company in Dubai,” he said.
The transfer was executed by Banco BIC, a bank at which Isabel was a director.
Isabel was appointed to run Sonangol in June 2016. She was removed from the job in November last year by Angola’s new president Joao Lourenco who has reversed several of his predecessor’s appointments.
Sonangol announced last December that it had opened an internal inquiry after discovering suspicious financial transfers with a value of tens of millions of dollars.
Isabel has used her personal Twitter account to deny any impropriety.
She is reported by Forbes to be the richest woman in Africa and has been dubbed “the princess” by critics of alleged corruption under her father.
Her appointment to Sonangol was also seen as a symbol of the nepotism that characterised Dos Santos’ 38-year rule.
Oil provides 70 percent of Angola’s revenues and almost all of its hard currency, but many of the country’s citizens are mired in poverty.