The New York Times quotes an unnamed analyst saying the entire incident might be part of a plan to derail diplomatic talks between Iran and the United States.
From the NYT:
Time magazine's Scott MacLeod has some thoughts on the conviction here.
One political analyst in Iran, who spoke on the condition of anonymity because of the delicate subject matter, said Ms. Saberi’s arrest could be part of the efforts by radical forces within the establishment who might be trying to sabotage any reconciliation with the United States.“There have been similar efforts in the past to sabotage efforts that were aimed at resuming ties with the United States,” he said. “Her jailing might be part of the same efforts."