Tehran: An Iranian nuclear scientist detained since 2010 has been executed, his family told BBC on Sunday. Shahram Amiri's mother said the scientist's body had been returned to their hometown with rope marks around his neck, showing that he was hanged. The scientist, who was born in 1977, went missing after taking a pilgrimage to Mecca in 2009. Amiri was held at a secret location after returning from the US, where he said he had been forcibly taken by the Central Intelligence Agency, BBC reported. In a video recording -- apparently made in the US -- he said, "They took me to a house located somewhere that I didn't know. They gave me an anaesthetic injection." However, he returned to Iran in 2010. He was reportedly tried for treason and arrested in 2011, BBC added. Some reports said he had "in-depth knowledge" of Iran's nuclear programme.