How to TURN THE BACK LIGHT OFF MY IPHONE 4?

MY FLASH LIGHT OF IPHONE 4 WON't GO OFF

Well is it the Camara or something cuase if it is Camara there's a butten that says Auto at the top left corner and put off or if it's not that you can go to Settings and click Brightness I hope this helps I also have an IPhone 4

Go to Settings and look for it.