How do I stop sound from looping on button press again

I have a simple button script for a two state button, but I’m having trouble trying to figure out how to make the sound stop looping when I press the button again. Here is what my script looks like.

//var levelToLoad : String;
var mouseUpTexture : Texture2D;
var mouseDownTexture : Texture2D;
var beep : AudioClip;
var SurveillanceSoundFX : AudioClip;

function OnMouseDown(){
     guiTexture.texture = mouseDownTexture;
     audio.loop = true; audio.clip = SurveillanceSoundFX; audio.Play();

function OnMouseUp(){
     guiTexture.texture = mouseUpTexture;
     yield new WaitForSeconds(0.3);
     //Do Something

Never mind… figured it out, I just needed to add this to my mouseDown function:

if (audio.isPlaying)
       audio.Pause ();
       audio.Play ();