Former Comoros president Ahmed Abdallah Sambi was on Tuesday taken into custody amid an investigation into an economic citizenship program introduced by his government, his family says.
Sambi has been under house arrest since May, a period in which he has been denied access to phones and computers.
An investigating judge however ordered that he be formerly detained. The former head of state has denied the accusations levelled against him linked to money that has allegedly gone missing from a scheme to sell passports to fund development.
Observers say his arrest came amid a crackdown on opponents of constitutional reforms on the Indian Ocean archipelago.