The Fifth Witness by Michael Connelly

Lawyer Mickey Haller has fallen on slightly hard times, as criminal defense cases have all but dried up due to the long U.S. recession. Ever adaptable, he has begun taking the cases of people who have had their homes foreclosed on, and it's turned out to be just what the banker ordered. When one of his clients, Lisa Trammel, is accused of murdering the bank vice president who is trying to take her home away, he's back in the saddle again, taking the reins of what may turn out to be a high-profile criminal case.

Lisa has had some hard times too, being abandoned by her husband after he lost his job and the house payments got too far behind, then fighting a losing battle against the foreclosure mill that handled the paperwork (which may be a Mafia front). In the course of her fight, she started an organization, FLAG, that organizes protests against foreclosures, and has gained some national recognition (which didn't do a thing for her finances, evidently). The mortgage company that turned her over for foreclosure has taken out a restraining order against her, and she's no longer allowed to be within 100 yards of the bank.

Mickey has, since we last saw him, taken on an associate, fresh out of law school, the possibly lovely and talented Jennifer Aronson. Connelly does mention that Aronson is talented at legal shenanigans, but it's uncertain whether she's lovely or not, as she never really becomes a fully-fleshed character, serving merely as a foil for Mickey and someone with whom he is able to conduct a dialog that explores the ethical and personal ramifications of, as a criminal lawyer (is that redundant?), defending those whom one suspects or believes may be guilty.
That is really the theme of this story, and Haller, jaded veteran, mostly tries not to think about it too much, though we are evidently expected to, as it is discussed repeatedly throughout the story, and the ending itself reflects Mickey's nascent feelings on the matter.
The whodunnit part of the story is quite good - Haller puts on a Johnny Cochrane OJ defense, arguing that his client was not guilty, and could not have committed the crime, given the physical evidence. There are two clues mentioned very early that turn out to be the crucial bits of information that reveal the true guilty party. I have to admit I missed them at first, and only at the big reveal did I have my "Aha!" moment.

Connelly is always good at weaving a strong story, but is, at least in this case, a bit weak on making his bit players more real.