The spy saga of an Iranian nuclear scientist ended with his execution

The Iranian nuclear scientist who may have given information to the United States about his country's nuclear codes was hanged for treason — the final chapter in a long tale of intrigue, espionage and state secrets.

Shahram Amiri's mother told the BBC that she received her son's body on Saturday, with rope marks around his neck, suggesting he had been hanged. His execution marks the first time that the Iranian government has publicly acknowledged that it "secretly detained, tried and convicted" a man whom authorities once hailed as a national hero, the Associated Press wrote.

Amiri, who worked for Iran's Atomic Energy Organization, went missing in 2009 while on a pilgrimage to Mecca and reappeared one year later in the US in a series of videos posted online. His version of events was that he was drugged, abducted, interrogated, psychologically tortured and held against his will by the CIA, and that he wanted to return home to Iran. He eventually did return to Iran, via the Pakistani embassy in Washington, which has an Iranian interests section, since the US and Iran do not have diplomatic relations.

US officials scoffed at Amiri's claims, insisting that he had defected from Iran voluntarily and gave American intelligence "useful information." Officials also told the Associated Press in 2010 that Amiri was paid $5 million for information about Iran's nuclear program, but left the US without the money.

When he came back to Iran in 2010, Amiri said he had fled from US officials. The US said that he had been free to come and go as he pleased, and he only returned to Iran because of family problems he was having. Those problems may have been threats on his family by the Iranian authorities, although no one knows for sure.

He received a hero's welcome upon his return, but months later Iranian officials arrested and imprisoned him. They may have suspected he had been turned and was now acting as a double agent for the US, or they may have decided tat he really had given information about the nuclear program to Iran's enemies.

One batch of Hillary Clinton's emails released by the State Department last September shows people working with the then-Secretary of State, now Democratic presidential nominee, may have expressed concern over Amiri's impending departure to Iran. In one exchange between Clinton and her advisers, Richard Morningstar, then State Department special envoy for Eurasian energy writes, without citing Amiri by name, about someone who might well be the Iranian nuclear scientist:

"We have a diplomatic, 'psychological' issue, not a legal issue. Our friend has to be given a way out. We should recognize his concerns and frame it in terms of a misunderstanding with no malevolent intent and that we will make sure there is no recurrence….If he has to leave so be it. "

Last year, Iran reached a historic agreement with the United States and other members of the international community, vowing to curb its nuclear program in return for lifting crippling economic sanctions.