The victim died on the spot.
The assailant then went to his house nearby and shot himself in the left temple with the same gun, injuring himself seriously.
The 81-year-ld was initially rushed to Karditsa General Hospital and from there, due to the severity of his injury, to the University Hospital in Larissa, where he is hospitalised under police guard.
During a search of the 81-year-old's house, police found and confiscated the gun used in the incident as well as a hunting rifle and ammunition, gun bullets of varying diameters, an airgun, and three flare guns.
Karditsa security police are conducting a preliminary investigation into the causes of the shooting.