Who is Iran's Supreme Leader Ayatollah Ali Khamenei, where is he now and why is he a potential target for Israel and US?

Israel attacks Iran: Iran's Supreme Leader Ayatollah Ali Khamenei was not in Tehran when Israel launched a strike near his offices. He had already been moved to a secure location. Ayatollah Ali Khamenei became the supreme leader after his predecessor Ayatollah Khomeini died in 1989 and he oversees the military, state media and armed forces in Iran. Both the US and Israel see him as a potential target due to the threat of nuclear weapons.