Itachi had the Mangekyou Sharingan before he killed the Uchiha.
Tobi (Obito) had the Mangekyou Sharingan before the Uchiha Massacre.
Tobi used Kamui against Minato, which means he had the Mangekyou Sharingan.
Sasuke sees Itachi Mangekyou Sharingan when Itachi is being accused for killing Shisui Uchiha. Which is right before the massacre.