AI script gone wrong?

I am making a zombie AI but it seems that when it kills me it no longer chases anyone. Please help as I can not figure it out.

Here is the script:

torso = script.Parent.Torso
range = 50
armDmg=5
torDmg=10
target = nil

function findNearestTarget()
    plrs = game.Players:GetChildren()
    for i,plr in ipairs (plrs) do
        if plr.Character ~= nil then
            if plr.Character:findFirstChild("Humanoid") and plr.Character.Humanoid.Health>0 then
           tor = plr.Character.Torso
            if target ~= nil then
             if(torso.Position-tor.Position).magnitude < (torso.Position-target.Torso.Position).magnitude then
                print(plr.Name.." is in range")
                target = plr.Character
                break
            end
        elseif (torso.Position-tor.Position).magnitude <= range then
                print(plr.Name.." is in range")
                target = plr.Character
                break
                end
            end
        end
    end
end

function hitArm(hit)
    if hit.Parent ~= nil and hit ~=nil then
        if hit.Parent:findFirstChild("Humanoid") then
            hit.Parent.Humanoid:TakeDamage(armDmg)
        end
    end
end
function hitTorso (hit)
if hit.Parent ~= nil and hit ~=nil then
        if hit.Parent:findFirstChild("Humanoid") then
            hit.Parent.Humanoid:TakeDamage(torDmg)
        end
    end
end


script.Parent["Left Arm"].Touched:connect(hitArm)
script.Parent["Right Arm"].Touched:connect(hitArm)
script.Parent["Torso"].Touched:connect(hitTorso)    

while true do
    wait (.1)
    findNearestTarget()
    if target ~= nil then
        script.Parent.Zombie:MoveTo(target.Torso.Position,target.Torso)
    end
end