Cake\Controller\Component\AuthComponent::user PHP Method

    public function user($key = null)
    {
        $user = $this->storage()->read();
        if (!$user) {
            return null;
        }
        if ($key === null) {
            return $user;
        }
        return Hash::get($user, $key);
    }

 public function beforeDelete(Event $event, Entity $entity, ArrayObject $options)
 {
     if (empty($options['loggedInUser'])) {
         $options['loggedInUser'] = $this->_Auth->user('id');
     }
 }