Mind Games — C.J. Koehler

Searching for a killer's motivation requires logic and insight into human nature, skills at which former priest Ray Koepp excels. The victim is Isaac Steiner, a prominent man in academic circles and one of the founders of a sociology research project in community living called Friar's Close. In this idyllic housing community, conceived as a refuge from urban violence, Steiner has been stabbed to death.
But, as Koepp discovers, life at Friar's Close is far from idyllic, and his own growing attraction to a woman who may be his prime suspect forces him to confront the myriad sides of human nature, including his own, as another murder leads him to the shocking truth.