respawning enemies that recognize player

Trying to get more mileage from my prefab enemies. In their ATTACK scripts they seek out the player by his transform - a public variable I drag and drop "player" into and all is well. When I respawn that enemy that field is empty so he ignores me . How rude. Question is what do I need to do to this script so that field isn't empty when the enemy prefab spawns? specifically , the error line is

"if(Vector3.Distance(transform.position,Player.position)

this is where the enemy is suppose to tell if I am close enough to attack

 public Transform Player;

is where I drag and drop the player into the script for the original enemy. but here's the entire script

 using UnityEngine;
 using System.Collections;
 
 public class neoNaziAttack : MonoBehaviour {
 
     public enum EnemyState{IDLE = 0, WALK = 1, RUN = 2, ATTACK = 3, KILL = 4};
     public GameObject enemy;
     public Transform Player;//adds the player to the script
     public int MaxDist= 8;//maximum distance the player can be before enemy stops chasing the player
     //public int NavDist= 8;
     public int NavSpeed= 8;
     public float MinDist= 1;//how close the player can be to enemy for enemy to start chasing player
     public EnemyState currentState;
     public GameObject getHim;
     Animator anim;
     public PlayerHealth playerHealth;
     private NavMeshAgent agent;
     public static bool PlayerDetected ;
     public bool PlayerDetected2 ;
     private bool jumping = false;//************this is the delay from hitreact
     public float timeWhileJumping = 2f;
     private bool jumping2 = false;//*****this is the delay from run to firing gun
     public float timeWhileJumping2 = 2f;
     public MonoBehaviour gun;
     public  GameObject naziWayOff;//turns off waypoints
 
     void HitByRay () {
         naziWayOff.SetActive  (false);
         anim.SetTrigger ("Hit");//ScoreManager.score += scoreValue;
         StartCoroutine(DelayAfterJump());
         agent.enabled = false;
         transform.LookAt(Player);
         anim.ResetTrigger ("walk");
         anim.ResetTrigger ("idle");
         anim.ResetTrigger ("idle2");
         anim.ResetTrigger ("attack");
         jumping = true;
     }
     void Start()
     {
         gun= enemy.GetComponent <naziRifle> ();
         anim = enemy.GetComponent<Animator>();
         agent = enemy.GetComponent<NavMeshAgent>();
         playerHealth = GameObject.FindWithTag("Player").GetComponent <PlayerHealth> ();
         //Player=Transform.FindWithTag("Player");
     }
     void Update()
     {
         PlayerDetected2 = PlayerDetected;
 
             agent.enabled = true;
     //    if (currentState == EnemyState.ATTACK)
             //agent.enabled = false;
         if(PlayerDetected ==true)
         MaxDist= 25;
         if(PlayerDetected ==true)
         naziWayOff.SetActive  (false);
         if(PlayerDetected ==true)
         agent.speed = NavSpeed;
         if(PlayerDetected ==true)
         agent.stoppingDistance = MinDist;
         if(PlayerDetected ==true)
         agent.acceleration = 7;
 ;
             if(playerHealth.currentHealth <= 0)
         anim.SetTrigger ("idle");
 
         if(Vector3.Distance(transform.position,Player.position) <= MaxDist)//if that object has the tag "Player"
         {
             PlayerDetected = true;
             if (PlayerDetected)
             {
 
                 transform.LookAt(Player);//Looks at the player
                 currentState = EnemyState.RUN;
 
 
             }
         }
         else if(Vector3.Distance(transform.position,Player.position) > MaxDist)
         {
             RoamAround ();
         }
         if (Vector3.Distance (transform.position,Player.position) < MinDist)
         {
             
             currentState = EnemyState.ATTACK;
             Attack ();
             
         }
         
         if (currentState == EnemyState.IDLE)
         {
 
             gun.enabled = false;
             RoamAround ();
         }
         else if (currentState == EnemyState.WALK)
         {
             anim.SetTrigger ("walk");
 
         }
         else if (currentState == EnemyState.RUN)
             
         {
             agent.SetDestination(getHim.transform.position);
             agent.enabled = true;
             anim.SetTrigger ("run");
             anim.ResetTrigger ("attack");
             anim.ResetTrigger ("idle");
             gun.enabled = false;
             anim.ResetTrigger ("stand");
         }
         else if (currentState == EnemyState.ATTACK)
         {
             //gun.enabled = true;
 
             anim.ResetTrigger ("run");
 
 
 
         }
         else if (currentState == EnemyState.KILL)
         {
             //anim.Stop ("machinegunblast");
             //GetComponent<Animation>().CrossFade (enemyKill.name);
         }
         
     }
     void RoamAround()//__________________________________________________________________________________________________________________
     {
         gun.enabled = false;
         naziWayOff.SetActive  (true);
 
     }
     public void Attack()
     {
         anim.SetTrigger ("aim");
         agent.enabled = false;
         StartCoroutine(DelayAfterJump2());
         anim.ResetTrigger ("run");
         anim.ResetTrigger ("idle");
         jumping2 = true;
         if(playerHealth.currentHealth <= 0)
             anim.SetTrigger ("idle");
         if(playerHealth.currentHealth <= 0)
             currentState = EnemyState.IDLE;
 
     }
 
 private IEnumerator DelayAfterJump(){
     yield return new WaitForSeconds(timeWhileJumping);
 
         MaxDist= 30;
 
     anim.ResetTrigger ("Hit");
     jumping = false;
         agent.enabled = true;
         agent.SetDestination(getHim.transform.position);
 }
     private IEnumerator DelayAfterJump2(){
         yield return new WaitForSeconds(timeWhileJumping2);
         gun.enabled = true;
         jumping2 = false;
         anim.ResetTrigger ("aim");
     }
 }