Six Egyptian rights groups issued a statement outlining violations in the military trial of 15 men who were executed in Egypt on Tuesday.

The statement, which was issued on Tuesday and signed by six local rights organizations —including the Egyptian Initiative for Personal Rights, the Egyptian Commission for Rights and Freedoms and the Association for Freedom of Thought and Expression — identified severe violations of due process that culminated in one of the largest group executions in Egypt’s recent history.

Fifteen detainees were executed by Egyptian authorities on December 26, less than two months after being convicted of killing security forces in North Sinai.

Those executed were convicted of the murder of nine Armed Forces personnel in the Safa checkpoint in North Sinai in 2013, the attempted murder of security forces in Arish, illegally surveilling the movements of the military personnel in North Sinai and the possession of explosives, among other charges.

The final verdict was issued by the Supreme Military Court of Appeals, which sentenced the 15 people to death on November 13.

According to the statement, the families of the 15 men only became aware of the executions after they took place, despite the stipulation in Egypt’s Criminal Code that relatives of those sentenced to death have the right to visit them on the day of their execution.

The statement added that the case files, including the military prosecution’s investigations and the military court sessions, also reveal several violations to the rights of the executed men to a fair trial.

The statement alleges that the men were forcibly disappeared for up to four days in illegal places of detention, including a police camp and military base in North Sinai.

The prosecution also documented signs of torture on the bodies of the defendants, according to the statement. In one case, the prosecution documented that the autopsy on Ibrahim Salem, one of the men executed on Tuesday, showed injuries to his eyes, wrists, right arm and leg in addition to bruises on his chest, abdomen and back.

In addition to apparent torture during interrogation, the statement said that nine of those executed did not have legal representation throughout the trial, while the others were represented by lawyers appointed by the prosecution. The statement added that the documented testimony of the investigative officer has him vaguely identifying “trusted sources” as the basis of his investigation.

Meanwhile, a military court sentenced 10 people to death on Wednesday, including former military officer Hesham Ashmawy, on charges related to terrorist attacks claimed by Sinai-based militant groups.

Four others were sentenced to life in prison in the same case, with another four defendants receiving 15 years in prison and 83 defendants acquitted.

The defendants were charged with involvement in a number of terrorist attacks, including the attack on security forces in the area of Dabaa in August 2014, the assassination of police officer Karim Fouad in Egypt’s north coast in March 2015, the bombing of the Italian Consulate in Cairo in July 2015, the attack on the Farafra security checkpoint in Egypt’s Western Desert and the bombing of a national security building in Shubra.

Egypt has been criticized by local and international rights organizations for issuing hundreds of death sentences in the last four years, mainly targeting those accused of having ties to the Muslim Brotherhood and militant groups. However, the majority of these death sentences have not been carried out.