The admission from the Egyptian military, which rules the country, came after the story had already circled the globe, underscoring its sweeping crackdown on civil society groups, artists, activists and intellectuals in the three years since former President Mohamed Morsi was overthrown.
Most of the rioters convicted with Ali were supporters of the Muslim Brotherhood, Morsi's party.
Critics have accused the military of a brutal crackdown on dissent since Morsi's 2013 ousting. That crackdown has since extended to civil society groups, as The Washington Post's Erin Cunningham reported last May, and "artists, activists and intellectuals," as Cunningham reported earlier this month.
Even Secretary of State John F. Kerry weighed in, urging Egyptian authorities this summer to better target their campaign against anti-government militants.
“It is important to distinguish between those who use violence to achieve their ends and others who seek peacefully to participate in a political dialogue, even if what they say may sometimes make people uncomfortable,” Kerry said at the time.