The speaker of Tunisia's dissolved parliament appeared in court on Thursday as part of a case involving money-laundering and "incitement to violence".
Rached Ghannouchi, who also heads the Ennahdha party, was previously questioned on the case in July.
Other Ennahdha members are also facing prosecution over suspicious transactions involving Instalingo, a digital content production firm.
The company has been under investigation since last year for allegedly "plotting against state security" and inciting violence.
After a 14-hour hearing, the investigating judge released Ghannouchi, his lawyer Sami Triki said.
He added that Ghannouchi will still be prosecuted in this case, but that no date for the next hearing has been set yet.
Earlier in the day, the 81-year-old arrived at court in the coastal city of Sousse, where he told journalists the case was an "empty file" and an "invented problem".
"This is trumped-up and aimed at distracting the Tunisian people from the real problems we're facing," he said.
