PHP class_exists - getting Fatal error: Cannot redeclare clas instead?

I want to return an error message when two classes provided by the user/ developer don't exist.

core/model/Conan.php,

namespace core\model;

class Conan 
{
    var $bodyBuild = 'extremely muscular';
    var $birthDate = 'before history';
    var $skill = 'fighting';

    public function methodConan()
    {
        return 'The methodConan from namespace core\model';
    }
}

local/model/Conan.php,

namespace local\model;

class Conan 
{
    var $bodyBuild = 'very skinny';
    var $birthDate = '1963';
    var $skill = 'comedy';

    public function methodConan()
    {
        return 'The methodConan from namespace local\model';
    }
}

index.php,

define ('WEBSITE_DOCROOT', str_replace('\\', '/', dirname(__FILE__)).'/');

include 'core/helper/BaseClassAutoloader.php';

// Autoload the core & local classes.
$autoloader = new BaseClassAutoloader([
    'local/model/',
    'core/model/'
]);

if (class_exists('\foo\model\Conan')) 
{
    echo 'from local';
}
else
{
    if(class_exists('\boo\model\Conan'))
    {
        echo 'from core';
    }
    else
    {
        echo 'both don\'t exist';
    }

}

I suppose to get 'both don\'t exist' as the result, I get this error instead,

Fatal error: Cannot redeclare class local\model\Conan in C:\wamp\www...\local\model\Conan.php on line 8

It doesn't really make sense!

Is it something wrong with my autoload below??

autoload class,

class BaseClassAutoloader
{
    public function __construct($directory) 
    {
         $this->directory = $directory;

         spl_autoload_register(array($this,'getClass'));
    }

    private function getClass($class_name)
    {
        if(is_array($this->directory)): $mainDirectories =  $this->directory;
        else: $mainDirectories =  array($this->directory); endif;

        $subDirectories = [];

        $namespace = "\\";
        $isNamespace = false;

        $parts = explode($namespace, $class_name);

        if(strpos($class_name, $namespace) !== false) 
        {
            $isNamespace = true;
        }

        $fileNameName = end($parts).'.php';

        foreach($mainDirectories as $pathDirectory)
        {
            $iterator = new RecursiveIteratorIterator
            (
                new RecursiveDirectoryIterator(WEBSITE_DOCROOT.$pathDirectory), // Must use absolute path to get the files when ajax is used.
                RecursiveIteratorIterator::SELF_FIRST
            );

            foreach ($iterator as $fileObject) 
            {
                if ($fileObject->isDir()) 
                {
                    $pathnameReplace = str_replace('\\', '/', $fileObject->getPathname());

                    $array = explode("/",$pathnameReplace);

                    $folder = end($array);

                    if($folder === '.' || $folder === '..') {continue;} 

                    $subDirectories[] = preg_replace('~.*?(?=core|local)~i', '', str_replace('\\', '/', $fileObject->getPathname())) .'/';
                }
            }
        }


        $merged_directories = array_merge($mainDirectories,$subDirectories);

        foreach($merged_directories as $pathDirectory)
        {
            if(file_exists(WEBSITE_DOCROOT.$pathDirectory.$fileNameName))
            {
                include WEBSITE_DOCROOT.$pathDirectory.$fileNameName;

                if($isNamespace === false) if (class_exists($class_name)) break;
            }
        }
    }

}

try using require_once instead of include