Saudi Arabia reportedly beheaded 37 of its citizens on Tuesday, marking the largest number of executions in a single day since 2016. The Associated Press reports that the body and severed head of a convicted Sunni extremist was also pinned to a pole and displayed publicly as a warning to others. The executed individuals were reportedly found guilty of killing security officers, cooperating with enemy organizations, and using explosives to attack security installations by the Specialized Criminal Court in Riyadh. Amnesty International said the majority of those executed were Shiite men, who were put to death “after sham trials.” The human rights group also said 11 of them were convicted of spying for Iran, and 14 others were convicted of “violent offenses” related to anti-government protests that occurred between 2011 and 2012. Ali Al-Ahmed, a Saudi dissident who runs the Gulf Institute in Washington, told the AP that 34 of those executed were Shiites, making it the “largest mass execution of Shiites” in the kingdom's history. The country's largest mass execution day occurred in 2016, when 47 people were put to death on terrorism-related charges.