Audio dont loss

This script work fine, when find the Image Target found the Audio start. But when loss the Image Target, the sound does not goes OFF still play. Please I need a help ________________________________________________________ using UnityEngine; // A custom handler that implements the ITrackableEventHandler interface. public class DefaultTrackableEventHandler : MonoBehaviour, ITrackableEventHandler{ AudioSource asrc; #region PRIVATE_MEMBER_VARIABLES private TrackableBehaviour mTrackableBehaviour; #endregion // PRIVATE_MEMBER_VARIABLES #region UNTIY_MONOBEHAVIOUR_METHODS void Start() { asrc = GetComponent(typeof(AudioSource)) as AudioSource; mTrackableBehaviour = GetComponent(); if (mTrackableBehaviour) { mTrackableBehaviour.RegisterTrackableEventHandler(this); } OnTrackingLost(); } #endregion // UNTIY_MONOBEHAVIOUR_METHODS #region PUBLIC_METHODS // Implementation of the ITrackableEventHandler function called when the // tracking state changes. public void OnTrackableStateChanged( TrackableBehaviour.Status previousStatus, TrackableBehaviour.Status newStatus) { if (newStatus == TrackableBehaviour.Status.DETECTED || newStatus == TrackableBehaviour.Status.TRACKED) { OnTrackingFound(); } else { OnTrackingLost(); } } #endregion // PUBLIC_METHODS #region PRIVATE_METHODS private void OnTrackingFound() { asrc.Play(); Renderer[] rendererComponents = GetComponentsInChildren(); // Enable rendering: foreach (Renderer component in rendererComponents) { component.enabled = true; } Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " found"); } private void OnTrackingLost() { Renderer[] rendererComponents = GetComponentsInChildren(); // Disable rendering: foreach (Renderer component in rendererComponents) { component.enabled = false; } Debug.Log("Trackable " + mTrackableBehaviour.TrackableName + " lost"); } #endregion // PRIVATE_METHODS }