FPS game SCORBOARD implementation ?

Hello guys,

My players when kill someone how can I understand who killed who , and increase kill score or death score , I am kinda new on photon ?

this is my bullet script =

private void OnTriggerEnter2D(Collider2D collision)

  {

    if (collision.CompareTag(TagManager.PLAYER_TAG))

    {

      myBody.velocity = Vector2.zero;

      CancelInvoke("DeactivateBullet");

      anim.enabled = true;

      anim.SetBool(TagManager.EXPLODE_ANIMATION_PARAMETER, true);

      if (!dealthDamage)

      {

        dealthDamage = true;

        collision.GetComponent<HealthSystemLast>().GiveDamageToPlayer();

      }

    }

And this is my HEALTH SCRIPT


public class HealthSystemLast : MonoBehaviourPunCallbacks,IPunObservable

{

  [SerializeField]

  private int health = 100;

  private int currentHealth;

  [SerializeField]

  private HealthBar healthBar;

  // [SerializeField]

  private Text killText;

  

  private void Start()

  {

   currentHealth = health;

    healthBar.SetMaxHealth(health);

  }

  public void OnPhotonSerializeView(PhotonStream stream, PhotonMessageInfo info)

  {

    // sync health

    if (stream.IsWriting)

    {

      stream.SendNext(health);

    }

    else

    {

      // if we are reading

      health = (int)stream.ReceiveNext();

          }

  }

  [PunRPC]

  public void GiveDamageToPlayer()

  {

    health -= 10;

    healthBar.SetHealth(health);  

    if(health <= 0)

    {   

  StartCoroutine(Respawn());

    }


  }


  private void SetKillText()

  {

     

    // killText.text = killcount.ToString()+" Deaths";

 

  }


  IEnumerator Respawn()

  {


    transform.position = new Vector3(1115, 109, 110);

    health = 100;

    healthBar.SetHealth(health);

    GetComponent<PlayerMovement>().enabled = false;

    GetComponent<PlayerShootingManager>().enabled = false;

   

    

    yield return new WaitForSeconds(3.0f);

    SetKillText();

    

    GetComponent<PlayerShootingManager>().enabled = true;

    transform.position = new Vector3(0, 10, 0);

    GetComponent<PlayerMovement>().enabled = true;

  }

}


Also some times bullets are touching player and health not decrase