My scoreboard kill variable doesn't work for some reason

[TheSckwadbros999]

on death:
   attacker is a player: 
      add 1 to {kills.%player%}     this isn't working with my scoreboard instead it gives the player who dies the kill idk why?

[BanditEagle]

you are adding 1 to the person who died, not the one who attacked. use "{kills::%attacker%}" instead.

[_Tarna_]

You should use attacker and victim in events such as on death. Player should still work but it is better to use attacker and victim.

[TheSckwadbros999]

on my scoreboard I have it so its looped and {kills::%loop-attacker%} doesn't work  

[_Tarna_]

Just now, TheSckwadbros999 said:

on my scoreboard I have it so its looped and {kills::%loop-attacker%} doesn't work  

If you are looping all players, its loop-player. Attacker and victim are only used in events like death and damage.