lookat wont track target

Hi community, im trying to do this without asking for help, but am really struggling getting my player to keep looking at target when clicked. it looks at target, but when I move it stops looking, im tryin to keep it locked until either target destroyed or when deselect. any hint or tips would be apprieciated as I've been stuck for over a day and can find nothing on forum about problem. thanks

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 public class Targeting : MonoBehaviour {
     
  
   private Transform selectedTarget;
   
   void Update(){
     if (Input.GetMouseButtonDown(0)){ // when button clicked...
       RaycastHit hit; // cast a ray from mouse pointer:
       Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
       // if enemy hit...
       if (Physics.Raycast(ray, out hit) && hit.transform.CompareTag("Enemy")){
         DeselectTarget(); // deselect previous target (if any)...
         selectedTarget = hit.transform; //set the new one...
         SelectTarget(); // and select it
       }
     }
   }
 
   private void SelectTarget(){
     selectedTarget.renderer.material.color = Color.red;
     transform.LookAt(selectedTarget.transform);
   }
 
   private void DeselectTarget(){
     if (selectedTarget){ // if any guy selected, deselect it
       selectedTarget.renderer.material.color = Color.blue;
       selectedTarget = null;
     }
   }
 }