The Ghost Murders

A little bit of confusion here.  I jumped the gun and posted a clew to another cover (Noose of Death) before tying up this one.  I now understand why Agent T was mystified by the clews apparently coming from different covers.  My bad.
I love this cover despite its problems.  The rendering isn't top notch but it has the secret code icons as wallpaper and there is the ring and the clock has struck twelve.  Kinda fun.  I haven't read this one but this review gives the tale top marks.  The original title was "The Cigarette Cipher" and that makes much more sense for this cover.  Of course having "Ghost" and "Murders" in the title is far more titillating  than "Cigarette".