local function removeCallbacks(player, callbacks)
	if not IsValid(player) then
		return
	end

	for _, callbackId in pairs(callbacks) do
		player:RemoveCallback(callbackId)
	end
end

function FrontierGainOnTeammateDeath(_, activator)

	local callbacks = {}

	local check

	local terminated = false
	
	anyonediedCallback = AddEventCallback("player_death", function(eventTable)

		local victim = Entity(eventTable.victim_entindex)
		local victimPos = victim:GetAbsOrigin()
		local activatorPos = activator:GetAbsOrigin()

		if victim == activator then
			terminate(anyonediedCallback)
			anyonediedCallback = nil
			return
		end

		if victim.m_iTeamNum == activator.m_iTeamNum and victimPos:Distance(activatorPos) < 600 then
				activator.m_iRevengeCrits = activator.m_iRevengeCrits + 2	
				local allPlayers = ents.GetAllPlayers()
					for _, player in pairs(allPlayers) do	   
						player:AcceptInput("$PlaySoundToSelf", "weapons/widow_maker_dry_fire.wav")
					end				

			local teleParticle = ents.CreateWithKeys("info_particle_system", {
				effect_name = "teleportedin_blue",
				start_active = 1,
				flag_as_weather = 0,
			}, true, true)	
			teleParticle:SetAbsOrigin(activator:GetAbsOrigin())
			teleParticle:Start()	

			timer.Simple(1, function ()
				teleParticle:Remove()
			end)				
		end				

	end)	

	local function terminate(eventcallback)
		if terminated then
			return
		end

		terminated = true

		timer.Stop(check)
		removeCallbacks(activator, callbacks)
		RemoveEventCallback(eventcallback)
		eventcallback = nil

	end

	check = timer.Create(0.015, function()

		if not IsValid(activator) or not activator:IsAlive() then
			terminate(anyonediedCallback)
			return	
		end		

	end, 0)

	callbacks.died = activator:AddCallback(ON_DEATH, function()
		terminate(anyonediedCallback)
		anyonediedCallback = nil
	end)
		
	callbacks.removed = activator:AddCallback(ON_REMOVE, function()
		terminate(anyonediedCallback)
		anyonediedCallback = nil
	end)
	callbacks.spawned = activator:AddCallback(ON_SPAWN, function()
		terminate(anyonediedCallback)
		anyonediedCallback = nil
	end)
end