Arash Khamooshi nearly broke down and cried. The Isna News Agency photographer said he doesn't know how he managed to keep it together to capture the emotional images shared all over the world Friday.
Myriam Hosseinzadeh approached the man accused of killing her teenage son, slapped him and shouted "forgiven."
Iran allows the family of the victim to drop capital punishment, but it is up to authorities to determine when and if the prisoner is released.
The man accused of stabbing her son with a kitchen knife during a street brawl -- too had a mother. She hugged and tried to comfort Hosseinzadeh.
A dream prompted Hosseinzadeh's compassionate act, The Guardian reported. In the dream, she said, her son asked her to forgive his killer.