Iran’s President Ebrahim Raisi and Foreign Minister Hossein Amir-Abdollahian were found dead Monday after their helicopter crashed due to “technical failure.” Search and rescue teams combed through the mountainous, forested area near the city of Jolfa for hours before discovering the helicopter. There were no survivors.

Raisi was a “hardliner” conservative who gained a negative reputation for his roles in public executions and repression against peaceful dissent in Iran. In 1988, he was appointed to the “Death Commission” by then–Supreme Leader Ruhollah Khomeini, a group that reportedly led to the execution of thousands of prisoners who were then buried in mass unmarked graves. He has also faced criticism from Iranian women and the West for ordering the strict enforcement of hijab policy; despite women across Iran increasingly refusing to wear hijabs in public, Raisi’s government sought to push legislation to punish hijabless women.

Raisi had also been viewed as a possible successor to Iran’s current Supreme Leader Ayatollah Ali Khamenei, even as some Iranians at home and abroad have been calling for an end to Shiite clerical rule.

In view of rising tensions between Iran and Israel—recently culminating last month in Israel’s strike against an Iranian consulate in Syria and Iran’s counterstrike on Israel—some are theorizing that Israel may have had something to do with Raisi’s death. Others are speculating that the crash may have been an inside job to clear the way for Khamenei’s son, Mojtaba Khamenei, to become Supreme Leader.

Iran’s Khamenei has stressed that there will be “no disruption” in Iranian state affairs. He has already declared Mohammad Mokhber as acting president and stated that, per the Iranian constitution, elections will be organized for a new president within 50 days.