Attempt to index number with 'human' error. I'm not sure what happened?

In the output, it's saying on line 65 there's an error saying: 'Attempt to index number with 'human'' although I'm quite sure I did it right.

local CollectionService = game:GetService("CollectionService")

local zombies = {}

function updateTarget() -- creating function to update the target
	local humans = CollectionService:GetTagged("Human")
	for _, zombie in pairs(zombies) do
		local target = nil
		local dist = 200
		for _, human in pairs(humans) do
			local root = human.RootPart
			if root and human.Health > 0 and (root.Position - zombie.root.Position).magnitude < dist and human.Parent.Name ~= zombie.char.Name then
				dist = (root.Position - zombie.root.Position).magnitude
				zombie.target = root
			end
		end
	end
end

spawn(function()
	while wait(1) do
		updateTarget()
	end
end)

function findPath(zombie)
	local x = math.random(-50,-50)
	local z = math.random(-50,-50)

	local destination = Vector3.new(x,0,z)

	local path = game:GetService("PathfindingService"):CreatePath()
	path:ComputeAsync(zombie.root.Position,destination)
	local waypoints = path:GetWaypoints()
	local currentTarget = zombie.target

	for _, waypoint in pairs(waypoints) do
		if path.Status == Enum.PathStatus.Success then
			if waypoint.Action == Enum.PathWaypointAction.Jump then
				zombie.human.Jump = true
			end
			zombie.human:MoveTo(waypoint.Position)
			local cooldown = zombie.human.MoveToFinished:Wait(1)
			if not cooldown then
				print("Got stuck!")
				zombie.human.Jump = true
				findPath(zombie)
				break
			end
			if not zombie.target then
				break
			elseif (currentTarget.Position - waypoints[#waypoints].Position).magnitude > 10 or currentTarget ~= zombie.target then
				findPath(zombie)
				break
			end
		end
		print("Path unsuccessful.")
		zombie.human.Jump = true
		findPath(zombie)
	end
end

function moveHandler(zombie)
	while wait(1) do
		if zombie.human.Health <= 0 then
			break
		end
		if zombie.target then
			findPath(zombie)
		end
	end
end

function tagHuman(instance)
	local human = instance:FindFirstChildWhichIsA("Humanoid")
	if human then
		CollectionService:AddTag(human,"Human")
	end
end	

function removeZombie(zombie)
	local index = table.find(zombies,zombie)
	table.remove(zombies,index)
	wait(5)
	zombie.char:Destroy()
	zombie.clone.Parent = workspace
end

function addZombie(zombieHumanoid)
	table.insert(zombies,{
		char = zombieHumanoid.Parent,
		root = zombieHumanoid.RootPart,
		human = zombieHumanoid,
		target = nil,
		clone = zombieHumanoid.Parent:Clone()
	})
	for _,zombie in pairs(zombies) do
		if zombie.human == zombieHumanoid then
			zombie.human.Died:Connect(function() removeZombie(zombie) end)
for i, v in pairs(zombie.char:GetDescendants()) do
	if v:IsA("BasePart") and v:CanSetNetworkOwnership() then
		v:SetNetworkOwnership(nil)
	end
end
spawn(moveHandler, zombie)
break
end
end
end

workspace.ChildAdded:Connect(tagHuman)
workspace.ChildAdded:Connect(function() print("Hi") end)

CollectionService:GetInstanceAddedSignal("Human"):Connect(function(zombieHumanoid)
	addZombie(zombieHumanoid)	
end)

function initialize()
	for _, v in pairs(CollectionService:GetTagged("Zombie")) do
		local found = false
		for _, x in pairs(zombies) do
			if x.human == v then
				found = true
			end
		end
		if not found then
			addZombie(v)	
		end
	end
end

initialize()

function attack(zombie)
	local human = zombie.target.Parent:WaitForChild("Humanoid")
	human:TakeDamage(math.random(15,25))
end

spawn(function()
	while wait(0.5) do
		for _, zombie in pairs(zombies) do
			if zombie.target then
				if (zombie.target.Position -  zombie.root.Position).magnitude < 5 then
					attack(zombie)
				end
			end
		end
	end
end)

I think you should use humanoid.Died Event.

So here is the moveHandler function rewritten:

function moveHandler(zombie)
	while wait(1) do
		zombie:FindFirstChild("human").Died:Connect(function()
			break
		end)
		if zombie.target then
			findPath(zombie)
		end
	end
end

see if it errors this time.