How to duplicate or spawn the enemy ai that will work as orginal?

When i duplicate the enemy ai the original one is working well but the duplicate one is only idle. it does not walk or attack. but when i attack the duplicate one both are die. Please help me…

Here is my script…
using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class chase : MonoBehaviour {

public Transform player;
static Animator anim;

public Slider healthbar;

// Use this for initialization
void Start () 
{
	anim = GetComponent<Animator> ();
}

// Update is called once per frame
void Update () 
{
	if (healthbar.value <= 0) return;

	Vector3 direction = player.position - this.transform.position;
	float angle = Vector3.Angle (direction, this.transform.forward);
	if (Vector3.Distance (player.position, this.transform.position) < 10 && angle <60) 
	{

		direction.y = 0;

		this.transform.rotation = Quaternion.Slerp (this.transform.rotation,
			Quaternion.LookRotation (direction), 0.1f);

		anim.SetBool ("isIdle", false);
		if (direction.magnitude > 5) 
		{
			this.transform.Translate (0, 0, 0.05f);
			anim.SetBool ("isWalking", true);
			anim.SetBool ("isAttacking", false);
		} 
		else 
		{
			anim.SetBool ("isAttacking", true);
			anim.SetBool ("isWalking", false);
		}
	} 
	else 
	{
		anim.SetBool ("isIdle", true);
		anim.SetBool ("isWalking", false);
		anim.SetBool ("isAttacking", false);
	}

}

}

wow I’m facing a very similar problem, did you get it fixed and how.