"The first hearing of a member of the Transitional Military Council took place on Monday," an associate of committee head Nabil Adib told AFP, without revealing the name of the questioned officer.

The Transitional Military Council, now dissolved, was established in April last year after the army deposed longtime dictator Omar al-Bashir following months of mass protests against his rule.

Demonstrators remained encamped outside army headquarters in the capital Khartoum even after Bashir fell from power, to demand a transition to a civilian government

On June 3, 2019, gunmen in military fatigues raided the sit-in, shooting and beating protesters.

The SUNA state news agency earlier this month quoted the media adviser to army chief Abdel Fattah al-Burhan as saying that "all members" of the dissolved TMC would have to "present themselves" to an investigative commission.

Burhan had himself headed the TMC, which was superceded in August 2019 by the Sovereign Council, a power-sharing comprised of military and civilian figures.

Burhan has likewise chaired the Sovereign Council, the highest executive body in the country's shaky transition, but he has lately criticised the power-sharing institutions.

The Sudan Human Rights Commission, citing police records, said 85 people died in the June 2019 crackdown, while medics linked to the protesters said over 100 were killed.

A spokesman for the TMC acknowledged days after the killings that "mistakes happened" after it ordered commanders to "come up with a plan to disperse" the protesters.

An initial probe by military officials and prosecutors then found that some members of the paramilitary Rapid Support Forces (RSF) and other security forces were involved in the killings.

Adib, a veteran human rights lawyer, was named to lead the investigative committee in October last year by Prime Minister Abdalla Hamdok.

The June 3 crackdown was the bloodiest episode during the extended protests, which resulted in several hundred deaths, according to various reports.