Iran imposes the death penalty for "spreading mischief in the land", a reference to the Quran 5:32. This verse is interpreted to apply to those who encourage conversion from Islam to Christianity. Leaving Islam for another religion is considered "Apostasy". According to Farsi Christian News Service, two Christian bloggers were entrapped and arrested in Isfahan on February 4th. The target of the entrapment operation seems to be bloggers rather than Christian converts as other family members were not arrested.
This Aljazeera video from March 24th acknowledges that bloggers in Iran who encourage conversion to Christianity are in danger of the death penalty for their activities.
Hat Tips to Nova Scotia Scott and Islam in Action