Dog Eat Dog : An Andy Carpenter Mystery (An Andy Carpenter Novel)

Before the guy gets taken away, he makes Andy and Laurie promise to look after the dog, which is an easy promise to make, since Andy is the founder of a dog rescue organisation. At the police station, the passerby is identified as Matthew Jantzen, who turns out to be wanted for murder. Andy is struck by the fact that Jantzen, a man supposedly on the run, would nevertheless intervene to help a dog, and even though Andy is never keen to take on a new case, he can't say no to someone who is clearly as much of a dog lover as he is.