Senegalese authorities have told Karim Wade, the son of former president Abdoulaye Wade, not to leave the country pending the results of a corruption investigation, a justice ministry adviser said on Friday.
Karim Wade served as a 'super minister' in charge of more than a third of the West African nation's budget during his father's presidency, which ended after elections this year.
The new president, Macky Sall, has said millions of dollars are missing from the state treasury, and has asked former colonial master France, as well as the United States and Britain, to help recover state assets.
"The investigators made it clear to Karim Wade that he can not leave the country," Macoumba Mbodj told Reuters, referring to a recently established court looking into graft.
Karim Wade was called back from France, where he and his father have been living since March elections, for questioning on Thursday that lasted more than 10 hours.
Special prosecutor Alioune Ndao said last week that Karim Wade and four other former ministers were being investigated on corruption allegations.
The former president has said the investigation into his son is unfair, and has threatened Sall with a lawsuit alleging graft if he does not drop it.
"This is a witch hunt, and this court has no jurisdiction to investigate former ministers," a spokesman for the Wade family, Ousmane Ngom, said on Friday.
Wade served as president for 12 years during which he won praise for driving big development projects including roads and an airport, but drew criticism for failing to stem worsening power cuts and rising food prices.
His decision to run for a third term in elections triggered widespread protests, though - in a move that shored up Senegal's democratic credentials - he conceded defeat to Sall after early poll results showed he had lost.
(Editing by Richard Valdmanis and Louise Ireland)