Showing Rain With Violence by Dell Shannon

The rain brought problems - difficult, ugly, weird problems - for Lieutenant Luis Mendoza. Senseless killings, cold-blooded murders, suicides. To say nothing of a ruthless gang of B-girls whose knockout drops knocked their victims out for good.

And then, on his own doorstep, Mendoza stumbled across a clue to one of the most vicious crimes he had ever been called on to solve.