U.S. authorities, looking for a trace of ex-agent Robert Levinson for several weeks, suspect he was being held hostage, the Financial Times says.
The U.S. State Department would say only that Levinson was in Iran on private business.
A possible break came from Dawud Salahuddin, a U.S. citizen living in Iran since allegedly killing an Iranian opposition activist in the United States in 1980.
Salahuddin, known in Iran as Hassan Abdulrahman, said he met with Levinson on the Iranian island of Kish March 8 concerning an investigation into cigarette smuggling.
He said while he was being questioned about his passport, Levinson was believed to have flown to Dubai.