According to Iran's official IRNA news agency, the incident took place around 4 p.m. local time on Sunday, when the IRGC member was dismounting his car to enter his home in an eastern neighborhood of the Iranian capital.
The IRGC member, who has been identified as Hassan Sayyad Khodaei, was assassinated after two motorcyclists shot him five times before fleeing the scene.
IRIB news agency reported that three bullets hit him in the head and two bullets hit his hand.
The IRGC issued a statement soon after the assassination, saying that its former member was assassinated in a terrorist attack by counterrevolutionary elements.
The statement condoled with his family, adding that necessary measures have been taken to identify and arrest the assailant or assailants.
Following the assassination, head of Tehran Court of Justice, Ali Alqasi, ordered Tehran prosecutor to speed up efforts to identify and arrest those behind this criminal act.
Alqasi also stressed the need to expedite judicial measures aimed at the identification of the perpetrators of this assassination.