How do I check who killed someone else?

I am trying to figure out how to award points for killing, but I do not know how to check for the killer, I only know how to check for the one that has been killed, this is what I have tried so far:

function awardpoints(player,points)
	if player and points then
		local leaderstats = player:FindFirstChild("leaderstats")
		if leaderstats then
			local pointsvalue = leaderstats:FindFirstChild("Points")
			if pointsvalue then
				pointsvalue.Value = pointsvalue.Value + points
				
			end
		end
	end
end
function awardexp(player,exp)
	if player and exp then
		local leaderstats = player:FindFirstChild("leaderstats")
		if leaderstats then
			local expvalue = leaderstats:FindFirstChild("exp")
			if expvalue then
				expvalue.Value = expvalue.Value + exp
				
			end
		end
	end
end
game.Players.PlayerAdded:connect(function(player)
	player.CharacterAdded:connect(function(character)
		character:WaitForChild("Humanoid").Died:connect(function()
			local tag = character.Humanoid:FindFirstChild("creator")
			if tag ~= nil then
				if tag.Value then
					local KillerTag = character:FindFirstChild("KillerTag")
					if KillerTag then
						awardpoints(player,50)
						awardexp(player,100)
					else
						awardpoints(player,-500)
						awardexp(player,-1000)
					end
				end
			end
		end)
	end)
end)

This code rewards the player that got killed instead of the player that killed, there seems to be nothing wrong with the first two functions. Also it gives the right amount to the correlating person, but affects the one that got killed.