At least 87 people were killed when security forces broke up a protest on June 3, said Fath Al Rahman Saeed, the head of the investigative committee.
He said security forces fired live ammunition at protesters in Khartoum.
The protestors demanded the military cede power.
Saeed told a news conference officers had violated orders by moving forces into the sit-in area.
He said 168 people were wounded, with 48 of them hit by bullets.
He said, some outlaws exploited this gathering and formed another gathering.
