Hello, PKing admin here~
Looking at the logs, it shows that you dealt damage to a cop, and then the cop killed you immediately afterward.
There was no damage dealt to you by the officer or by any other party prior to you shooting the officer.
After reviewing the clip, it shows the officer taking his gun off safety while turned away from you. He was not aiming at you, initiating anything, or opening fire. You took no damage, shot a cop, and were then killed by the cop, which is what led me to view this as a valid PK.
Good luck with your appeal.