The Segbroek police station in The Hague borrowed the idea of putting compass marks on ceilings from an Amsterdam hotel, the Dutch daily De Telegraaf reported on Friday.
Muslims pray five times a day, facing east in the direction of Mecca. But the arrows in Segbroek pointed west.
"This is a really gigantic, stupid blunder," a police spokesman told the De Telegraaf.
"The faulty compass marks have been immediately corrected. It is a mystery for us how this could have possibly happened".
A mystery indeed! Another mysery is who's going to get their head hacked off for this gaffe...