Iranian president Mahmoud Ahmadinejad came to the US last week but it appears that his entire delegation didn't return to Iran. Ahmadinejad's photographer is reported to have filed the paperwork to seek asylum and remain in the United States. According to U.S law, once you've filed for asylum, you can legally remain within the country until a decision is made.
The photographer's reason for asylum is due to his political stance with his own government. During his trip with the Iranian president, he claimed that his superiors were pressuring him to photograph things he was not comfortable with. In the eyes of the Iranian officials, his lack of compliance means he is siding with the U.S. instead of Iran. This potentially puts he and his family in danger.
While the specific whereabouts of the photographer remain unknown, it does appear that the decision was premeditated. The family of the photographer fled Iran before the paperwork was filed and are reportedly attempting to come the U.S. as well.
For more, details, the story from CNN