Ten years after his detention in Beirut, Hannibal Gaddafi, the son of Libya’s late leader Muammar Gaddafi, appeared Thursday before Lebanese Investigative Judge Zaher Hamadeh in connection with the decades-old disappearance of prominent Shiite cleric Imam Mussa al-Sadr.

The questioning was held at the Beirut Justice Palace around 11 a.m. and attended by three defense lawyers representing Gaddafi, including a French attorney. Representatives of the legal team for Imam al-Sadr and his companion, who vanished with him in 1978, were also present.

Before the hearing, Inas Harrak, a member of Gaddafi’s defense team, said the session was “not a test for the Lebanese judiciary, but rather a test for the conscience of the Lebanese State.”

Imam Mussa al-Sadr, the founder of Lebanon’s Amal Movement and one of the country’s most influential Shiite leaders, disappeared during an official visit to Libya in August 1978 along with his companions Sheikh Mohammad Yaacoub and journalist Abbas Badreddine.

Hannibal Gaddafi was detained in Lebanon in December 2015 after being kidnapped by an armed group in the Bekaa Valley, reportedly in an attempt to extract information about al-Sadr’s fate. He was later handed over to Lebanese authorities, who charged him with withholding information related to the disappearance.

Gaddafi has since been held in custody, despite repeated calls by his defense team for his release on the grounds that he was a child at the time of al-Sadr’s disappearance and had no role in it. His lawyers argue that Lebanon is holding him unlawfully and that the investigation has become politicized.