Harmuzan “converted” to Islam and moved to Medinah, whereupon he planned the Persian revenge on the Arab Muslims. Harmuzan blamed the Commander of the Faithful Umar for the downfall of the Persian Empire, and it was thus that Harmuzan hatched the plan to assassinate the Caliph.
In Medinah, Harmuzan became close companions with a staunch Christian named Jafeena Al-Khalil
. Jafeena was a political pawn of the Roman ruler and had served as an official in Damascus, Palestine and Heerah; the defeat of Rome by the Muslims left its mark on Jafeena who–like Harmuzan–swore revenge. The third partner was a Jew by the name of Saba bin Shamoon (whose son would be Abdullah Ibn Saba, the notorious founder of the Shia movement).
Saba despised the Muslims who had expelled the Jews on charges of conspiracy. All three of these individuals–Harmuzan the Zoroastrian, Jafeena the Christian, and Saba the Jew–belonged to peoples who had grievances against the rise of Muslim dominance.
They hired Feroz Abu Lulu
, a Persian, who had recently been captured by the Muslims as a POW; he was a slave under a Muslim master. Abu Lulu stabbed Umar bin Khattab to death. A day before Umar had been assassinated, Abdur Rehman-–Abu Bakr’s son-–had seen Abu Lulu standing with Harmuzan and Jafeena. The three men were whispering to one another. As Abdur Rehman passed by, the three got startled and a double edged dagger fell to the ground. Abdur Rehman would later confirm that this was the same dagger that killed Umar. The murder of Umar was thus instigated by a coalition of a Roman Christian, a Jew, and a Persian Zoroastrian. It should be noted that the Prophet had prophecized that the Christians, Jews, and pagans would always be united against the Muslims.
Today, the modern day Shia venerate Abu Lulu, and they call him “Baba Shuja-e-din” which can be translated as “Honored Defender of Religion.” These Shia have a shrine erected for this murderer, located in the Iranian city of Kashan called the Abu Lulu Mausoleum wherein he is buried. The Shia travel from far distances to pray inside this shrine, and many of the Shia fast on the day that Umar was killed, and even pass out sweets. Feroz Abu Lulu is one of the venerated founding figures of Shia ideology; the same people who conspired to kill Umar were the ones who planted the seeds of the Shia movement.