A Cairo criminal court has acquitted Egyptian-Irish dual citizen Ibrahim Halawa, 21, of all charges in the 2013 case dubbed by the media as the "Al-Fatah Mosque case".
However, in its ruling on Monday, the court sentenced 43 defendants to 25 years in jail in the same case, including 21 defendants sentenced in absentia.
Of the 492 defendants in the case, 52 were aquitted, while the rest were given jail sentences ranging from 15 to 5 years.
The case dates back to August 2013 when supporters of ousted Islamist president Mohamed Morsi clashed with security forces near Cairo's Al-Fatah Mosque, leaving 44 people dead, with many more injured, including 22 policemen, according to Egypt's interior ministry.
The charges brought against the defendants included attacking security forces, vandalizing public buildings, attempted murder and murder.
The defendants included leading Muslim Brotherhood figure Salah Soltan and two activists linked to the Muslim Brotherhood – Ahmed El-Mogheer and Abdel Rahman Ezz – who are now living abroad.
On Monday, the court also acquitted Ibrahim Halawa's sisters Samia and Fatma of charges in the same case. They were previously released pending investigations and left the country to Ireland in November 2013.
The government of Ireland has been demanding Ibrahim Halwa's release since 2013.
In addition to Halawa, one other Egyptian-US dual citizen, Ahmed Etiwy, faced trial in the case and was sentenced to five years in prison on Monday.
Senator John McCain listed Etiwy among 20 holders of dual US-Egyptian citizenship currently detained in Egypt pending trial. In a statement issued in August, McCain demanded that US President Donald Trump intervene to secure their release.
The court rulings issued on Monday were of the first degree and can be appealed.