Dead Hunt by Beverly Connor

Clymene O'Riley is in prison for killing her husband-though Diane Fallon is sure she killed another, and suspects she may have left a veritable graveyard of dead men in her wake. Either way, Diane was happy to help put her behind bars. So when Clymene informs her that one of the prison guards may be in danger from a serial killer, Diane is suspicious. And when Clymene escapes from jail, Diane becomes the prime suspect in a bloody murder that puts her in the path of an angry killer who wants her dead...

Okay, I think this has been my absolute best book in the series so far. I mean, aside from the happens-every-time attack on Diane Fallon, which is getting beyond predictable and is well into the realm of ridiculous now.

* This book is part of the Diane Fallon Forensic Investigation series: One Grave Too Many (2004), Dead Guilty (2004), Dead Secret (2005), Dead Past (2007), Dead Hunt (2008), Scattered Graves (2008), Dust to Dust (2009), The Night Killer (2010), One Grave Less (2010)