The policeman, Naqibullah opened fire on Associated Press (AP) photographer Anja Niedringhaus in eastern Afghanistan during the first round of election.
Another AP correspondent Kathy Gannon was also critically injured following the incident which took place in eastern Khost province earlier in April this year.
The first verdict was announced by Kabul District Court where Naqibullah was found guilty of murder and treason over the attack.
Naqibullah was also sentenced to fours in prison for critically injuring the AP reporter Kathy Gannon.
The verdict and sentence can be reviewed to several stages under the Afghan law, which means that Naqibullah may appeal to a second court within 15 days and then ultimately to the Supreme Court.
No reason was given by Naqibullah during the court hearing regarding his intention to open fire on foreign journalists.
The defense lawyer of Naqibullah argued that the convict was not a normal person. However, his claims were rejected by judges after the convict correctly provided his name, age and the correct date.