The Tunisian government has denied that the former prime minister, Hamadi Jebali, has been arrested.
On Thursday, a post on his official Facebook page said Mr Jebali had been detained by the security forces.
The Islamist Ennahda party also demanded his release.
But the interior ministry now says it’s investigating a factory on land owned by the former leader’s wife – and that he’d insisted on accompanying her to a police station.
Critics accuse Tunisia’s president, Kais Saied, of trying to stifle dissent.
Last year he dissolved parliament and took executive powers.