The Mephisto Club by Tess Gerritsen

Yes, The Mephisto Club is the next installment of the Rizzoli and Isles series (book number six). 

The books jacket reads as follows:

 PECCAVI 

The Latin word is scrawled in blood at the scene of a young woman’s brutal murder: I HAVE SINNED. It’s a chilling Christmas greeting for Boston medical examiner Maura Isles and Detective Jane Rizzoli, who swiftly link the victim to controversial celebrity psychiatrist Joyce O’Donnell–Jane’s professional nemesis and member of a sinister cabal called the Mephisto Club.

On top of Beacon Hill, the club’s acolytes devote themselves to the analysis of evil: Can it be explained by science? Does it have a physical presence? Do demons walk the earth? Drawing on a wealth of dark historical data and mysterious religious symbolism, the Mephisto scholars aim to prove a startling theory: that Satan himself exists among us.

With the grisly appearance of a corpse on their doorstep, it’s clear that someone–or something–is indeed prowling the city. The members of the club begin to fear the very subject of their study. Could this maniacal killer be one of their own–or have they inadvertently summoned an evil entity from the darkness?

Delving deep into the most baffling and unusual case of their careers, Maura and Jane embark on a terrifying journey to the very heart of evil, where they encounter a malevolent foe more dangerous than any they have ever faced . . . one whose work is only just beginning.

I am going to say little about this book because honestly, The Mephisto Club was one of the most spine-tingling and sinister books I've read in quite sometime.  With that said, I would have to compare it to the terrifying suspense of Tami Hoag's novel Night Sins.  I sat with the hairs on my arms rising, my limbs shivering, and still had the inability to put it down.  While Jane and Maura remain strong and deliberate yet human characters, the supporting cast includes an array of dysfunction along with quirky players belonging to the Mephisto Foundation, and let's certainly not forget the evil wandering through the pages of this book disguised as a demon in human flesh, or is he?

Pick up a copy and find out the answers for yourself.  As for me, I can't wait to dive into the next Rizzoli and Isles novel.