Police Car Sound Effects

I apologize that this might not be the right place for this question, but maybe some one can help me.

I'm in charge of designing the sound effects for a film festival entree. What I still need to find is a really good police siren. Not a siren that any royalty free website would have, but a good sounding siren that goes through the different stages that a police car goes through, a handful of the shortsound bursts, then a section of the longer bursts and so on.