The trial of the eldest son of ex-Mozambican president Armando Guebuza, Ndambi Guebuza, has started in the capital Maputo.
The former president's son is being tried alongside 18 suspects in Mozambique’s biggest post-independence corruption case.
Mr Guebuza and former members of the State Information and Security Service (Sise) are among those expected to appear as defendants in the case whose hearings will run until 1 September.
They have not yet commented.
Former Finance Minister Manuel Chang is also wanted over the scandal and is fighting extradition from South Africa. He denies any wrongdoing.
The trial is being held in a large canvas tent in the grounds of a maximum-security prison in the outskirts of the capital, Maputo.
The city's courtrooms were deemed too small for the scores of lawyers, 70 witnesses and 250 media workers who have been accredited to attend.
Between 2013 and 2014, Mozambique borrowed about $2bn (£1.5bn) but only disclosed most of the debt to the International Monetary Fund (IMF) in 2016.
The money was allegedly used to buy a large tuna factory and a maritime security fleet, as well as to finance other deals involving companies in which the state is a leading shareholder.
The scandal plunged Mozambique into its worst financial crisis since independence in 1975.
It also led to the suspension of budgetary aid to Mozambique by its external partners.