Code grey / Clea Simon.

Enhanced descriptions from Syndetics:

Did a down on his luck former student steal a priceless book? Grad student and cat lover Dulcie Schwartz thinks not - and she sets out to prove it

It's spring break, and Dulcie Schwartz has stayed behind in almost-deserted Cambridge, Massachusetts to concentrate on her thesis. But when a former student turned vagrant, Jeremy Mumbles, is found injured, with a valuable missing book clutched in his arms, Dulcie can't seem to let it go. What was he doing with the book? And why has it turned up after all these years?

With Jeremy now the prime suspect for a series of break-ins in the area, Dulcie is determined to clear the unfortunate former scholar's name. But when she finds a connection between the book he was carrying and her own research into an anonymous Gothic author, the search for clues takes on a new intensity - and a new menace.