How to display errors on laravel 4?

I'm trying to create an app on Laravel 4 beta but I can't debug it because it doesn't show any error, display_errors is on, error_reporting is E_ALL and debug => true (config/app.php). When I try to do an error on public/index.php it shows a parse error, but when I do it on the router it just shows a blank page (White screen of death). How can I fix this?

Thank you