When his father was captured, placed in prison and charged with high treason on the order of Ioannis Kapodistrias, Georgios and his uncle Konstantinos decided to exact revenge, as the apprehension of their patriarch was an act worthy of death according to their family.

Konstantinos attempted to shoot Kapodistrias as he climbed the steps outside of the building, but the bullet missed and lodged in the church's wall where it remains visible to this day, and so he resorted to stabbing the governor in the stomach whilst Georgios impaled him through the heart, fatally wounding him.

As the pair were escaping, the Greek army officer Gen. Fotomaras (who had witnessed the assassination from his own window across from the church before coming down to tend to the governor) shot Konstantinos once in the temple, killing him instantly and simultaneously bursting his skull.

[citation needed] Georgios, however, managed to escape and hide in the French Embassy, but he surrendered to the Greek authorities after a few days.

His final request that the executioners not shoot him in the head so as to not mirror the brutality of his uncle's death which had so shocked and traumatized him.