Lifeless by Mark Billingham
My rating: 4 of 5 stars
Has DI Thorne sunk as low as he possible can sink? Not sure... but here, his father's dead, there's no love interest, and he's sent to do really boring, unnecessary work for Scotland Yard. To cheer himself up, or give himself something to do, he's volunteered to "live rough" to help find whomever is killing homeless people. The sad thing is, he finds it easy to fall into the life, finding a few friends to pass the time with and guide him to the best spots for free meals. Of course, he's not completely alone out there, as a few people in the force know where he is and he has a cell phone with which to check in daily. As always happens, it takes a flash of insight/coincidence for him to crack the case - all on his lonesome, even though he does have help from his colleagues.
There are flashbacks here to the events that precipitated all the killings as well as the killer's POV interspersed with the investigation and I'm not sure why every Thorne book has to include that. It's a gimmick, and distracting.