The best mystery that I have ever read is the " Skinwalkers". Its a very scary murder mystery about the Navajo changelings. The author cited many geological facts to make it feel very realistic.
My short mystery starter:
On a dark, gloomy night, I was strolling down Conneticut Avenue.
I heard a sound similar to a hungry lion, munching on a fresh kill, but it sounded a lot louder. Suddenly, a long yell echoed down a alley way.
THE END! FOR NOW!!