Destroy(GameObject) problem

 void Update () {
 
 
         RaycastHit hit;
         
         Vector3 forward = transform.TransformDirection (transform.up) * 1;
         Debug.DrawRay (transform.position,transform.up,Color.green);
         
         if(Physics.Raycast (transform.position,(transform.up), out hit)) {
             Debug.DrawRay (transform.position,transform.up,Color.red);
 
             if(hit.transform.gameObject.tag == "Enemy"&& Input.GetMouseButtonDown(0)) {
                 shoot = true;
                 print ("SHOOOt");
                 AIisDead = true; 
                 Destroy (hit.GameObject);
             }

´(This is a script attached to a gun) When the raycast hits a object with the tag enemy, that object needs to be destroyed. But i cant really find out how to do it. the "hit" is that object the raycast is "touching". And that is the object i want to destroy if i press the mouse button and the object is tagged enemy.

I tried doing in the way that from my enemys script, i destroy if the AIisDead from this script, is true. But that destroyed all the enemys in the scene.