The Midnight Man by Loren D Estleman

Opening Lines:

Look for us on starless nights when the moon is new. Look closely, because we are hard to see. We don’t run in packs like wolves or feral dogs; we fear each other as much as we fear the light. The shadows are our home and we know them as we know the staircase to your bedroom, the light switch on your bathroom wall.Look for us, but keep your distance.

We’re the midnight men, and the prey we are stalking could be you.