Tajbakhsh was arrested at his home in Tehran on May 11, 2007, as the fourth Iranian-American, after Ali Shakeri, Haleh Esfandiari, and Nazi Azima, to be incarcerated, detained, or put under house arrest in 2007. He was accused of crimes against national security for working with American organizations such as the Open Society Institute and Gulf 2000 project, and held in solitary confinement in Evin Prison for more than four months. In September 2007, Columbia University President Lee Bollinger demanded that Iranian President Mahmoud Ahmadinejad release Tajbakhsh in a widely publicized debate. Following a global campaign for his release involving high-level diplomatic efforts, he was allowed to leave Evin Prison on parole and be reunited with his wife in Tehran on September 19, 2007.