Problem with mobs

Hello, I'll expose my problem: I'm doing a 2D platform game, and I have ennemies that shoot you when they see you but , only the first one shoots you and the rest doesn't do anything. I'm a bit noob scripting so I've done a very basic AI and maybe is not the best way to do it :P If you can tell me why only the first one shoots me it would be fantastic.

There are the scripts:

 using UnityEngine;
 using System.Collections;
 
 public class Mob : MonoBehaviour {
 
     public GameObject player;
     public GameObject laser;
     public AudioClip a_laser;
     public AudioClip exterminar;
 
     private GameObject mob;
     private bool attack;
     private float time;
     private AudioSource audio;
 
     // Use this for initialization
     void Start () {
         mob = gameObject;
         audio = GetComponent<AudioSource> ();
     }
     
     // Update is called once per frame
     void FixedUpdate () {
         if (Vector2.Distance (player.transform.position, mob.transform.position) < 10) {
             attack = true;
         }
         if (attack) {
             time += Time.deltaTime;
             if (time>= 1) {
                 Invoke ("Ataca",0);
                 time = 0;
             }
         }
     }
 
     void Ataca () {
         audio.clip = a_laser;
         audio.Play ();
         Instantiate (laser, this.transform.position, Quaternion.identity);
 //        Debug.Log ("ataaaacaaaaa");
     }
 
     void OnCollisionEnter2D (Collision2D coll) {
         if (coll.gameObject.tag == "Piruleta") {
             Destroy (this.gameObject);
         }
     }
 
 }
 

And the laser prefab script:

 using UnityEngine;
 using System.Collections;
 
 public class Laser : MonoBehaviour {
 
     public Vector2 laser;
     public AudioClip a_muerte;
 
     private AudioSource audio;
     private Rigidbody2D rb;
 
     // Use this for initialization
     void Start () {
         audio = GetComponent<AudioSource> ();
         rb = GetComponent<Rigidbody2D> ();
     }
     
     // Update is called once per frame
     void FixedUpdate () {
         rb.AddForce (new Vector3(-0.1f,0,0));
     }
 
     void OnTriggerEnter2D (Collider2D coll) {
         if (coll.gameObject.tag != "Player") {
             Destroy (this);
         }
         else {
             Debug.Log ("laser.toca");
             audio.PlayOneShot (a_muerte,0.5f);
             Application.LoadLevel ("GameOvah");
             Destroy (this);
         }
     }
 }
 

Thank you very much for your attention!