Iranian security forces may have pressured nuclear scientist Shahram Amiri, hanged last week for spying for the United States, to admit to crimes he did not commit, his mother said in an interview this week.

Amiri leapt to the global spotlight in 2010 when he claimed first that U.S. agents had abducted him and then that he was in the United States of his own free will.

The same year, he returned to Iran, where he was welcomed as a hero but then detained and tried on charges that he divulged nuclear secrets.