Gain points when the player kill an enemy

Question

I want to gain 10 points when the player kill an enemy but I don't get it. I've created a method to add score on my PuntosPistas script in the Player, and just call the method inside of the CheckHealth of the Enemy but it don't sum 10 points in score. Can anybody help me? This is my code:

In the Enemy:

public class v_AIMotor : vCharacter
{
    GameObject Player;

    void Start ()
    {
        Player = GameObject.FindGameObjectWithTag("Player");
    }

    public void CheckHealth()
    {
        if (currentHealth <= 0 && !isDead)
        {

            isDead = true;
            Player.GetComponent<PuntosPistas>().KillEnemy ();
            print("10 points");
            DisableActions();
        }
    }
}

In the Player:

public class PuntosPistas : MonoBehaviour 
{
    public int Score;
    public Text TextoContador;

    void Start ()
    {
        Score = PlayerPrefs.GetInt("Score");
        TextoContador.text = "" + Score;
    }

    public void KillEnemy()
    {
        Score = Score + 10;
        TextoContador.text = "" + Score;
        PlayerPrefs.SetInt("Score",Score);
    }
}

Sorry! This is the full code where I call CheckHealth():

 #region AI Health

    GameObject Player;

    void Start ()
    {
        Player = GameObject.FindGameObjectWithTag("Player");
    }

    public void CheckHealth()
    {
        if (currentHealth <= 0 && !isDead)
        {
            isDead = true;
            Player.GetComponent<PuntosPistas> ().KillEnemy ();
            DisableActions();
        }
    }

    public void HealthRecovery()
    {
        if (currentHealth <= 0) return;
        if (currentHealthRecoveryDelay > 0)
        {
            currentHealthRecoveryDelay -= Time.deltaTime;
        }
        else
        {
            if (currentHealth > maxHealth)
                currentHealth = maxHealth;
            if (currentHealth < maxHealth)
                currentHealth = Mathf.Lerp(currentHealth, maxHealth, healthRecovery * Time.deltaTime);
        }
    }

    protected void RemoveComponents()
    {
        if (_capsuleCollider != null) Destroy(_capsuleCollider);
        if (_rigidbody != null) Destroy(_rigidbody);
        if (animator != null) Destroy(animator);
        if (agent != null) Destroy(agent);
        var comps = GetComponents<MonoBehaviour>();
        foreach (Component comp in comps) Destroy(comp);
    }

    public override void TakeDamage(Damage damage)
    {
        if (rolling || currentHealth <= 0) return;
        if (canSeeTarget() && !damage.ignoreDefense && !actions && CheckChanceToRoll()) return;
        // change to block an attack
        StartCoroutine(CheckChanceToBlock(chanceToBlockAttack, 0));
        // defend attack behaviour
        if (canSeeTarget() && BlockAttack(damage)) return;
        // instantiate hit particle
        var hitRotation = Quaternion.LookRotation(new Vector3(transform.position.x, damage.hitPosition.y, transform.position.z) - damage.hitPosition);
        SendMessage("TriggerHitParticle", new HittEffectInfo(new Vector3(transform.position.x, damage.hitPosition.y, transform.position.z), hitRotation, damage.attackName), SendMessageOptions.DontRequireReceiver);
        // apply damage to the health
        currentHealth -= damage.value;
        currentHealthRecoveryDelay = healthRecoveryDelay;
        // apply tag from the character that hit you and start chase
        if (!sphereSensor.passiveToDamage && damage.sender != null)
        {
            target = damage.sender;
            currentState = AIStates.Chase;
            sphereSensor.SetTagToDetect(damage.sender);
            if (meleeManager != null)
                meleeManager.SetTagToDetect(damage.sender);
        }
        // trigger hit sound
        if (damage.sender != null)
            damage.sender.SendMessage("PlayHitSound", SendMessageOptions.DontRequireReceiver);
        // update the HUD display
        if (healthSlider != null)
            healthSlider.Damage(damage.value);
        // trigger the HitReaction when the AI take the damage
        var hitReactionConditions = stepUp || climbUp || jumpOver || quickTurn || rolling;
        if (animator != null && animator.enabled && !damage.activeRagdoll && !hitReactionConditions)
        {
            animator.SetInteger("Recoil_ID", damage.recoil_id);
            animator.SetTrigger("HitReaction");
        }
        // turn the ragdoll on if the weapon is checked with 'activeRagdoll'
        if (damage.activeRagdoll)
            transform.SendMessage("ActivateRagdoll", SendMessageOptions.DontRequireReceiver);

        CheckHealth();
    }

    #endregion

And this is the error in console:

NullReferenceException: Object reference not set to an instance of an object
Invector.v_AIMotor.CheckHealth () (at Assets/Invector-3rdPersonController/Scripts/CharacterAI/v_AIMotor.cs:504)
Invector.v_AIMotor.TakeDamage (.Damage damage) (at Assets/Invector-3rdPersonController/Scripts/CharacterAI/v_AIMotor.cs:582)
UnityEngine.Component:SendMessage(String, Object, SendMessageOptions)
vMeleeManager:OnDamageHit(HitInfo) (at Assets/Invector-3rdPersonController/Scripts/MeleeCombat/vMeleeManager.cs:295)
UnityEngine.Component:SendMessageUpwards(String, Object, SendMessageOptions)
Invector.vHitBox:CheckHitProperties(Collider) (at Assets/Invector-3rdPersonController/Scripts/MeleeCombat/vHitBox.cs:68)
Invector.vHitBox:OnTriggerEnter(Collider) (at Assets/Invector-3rdPersonController/Scripts/MeleeCombat/vHitBox.cs:48)

Answer 1

Please investigate on the way you call CheckHealth(), it's not clear from your code. That code should be work if you call the method properly, try in this way:

public class v_AIMotor : vCharacter {
    GameObject Player;

    void Start ()
    {
        Player = GameObject.FindGameObjectWithTag("Player");
    }

    public void CheckHealth()
    {
        if (currentHealth <= 0 && !isDead)
        {

            isDead = true;
            Player.GetComponent<PuntosPistas>().KillEnemy ();
            print("10 points");
            DisableActions();
        }
    }
    
    void Update()
    {
        CheckHealth();
    }
}

Using Update is not the best way for sure, but should be do the job.