Sorrow's Anthem (The Lincoln Perry Mysteries) / Michael Koryta

Once Lincoln Perry and Ed Gradduk were friends. Then Perry became a cop, Gradduk turned dangerous, and their friendship imploded. Now, Gradduk is dead. And Perry wants to use his PI license to prove that whatever else his childhood friend might have been, he wasn't a murderer.
 
For the police, this case is over. The woman Gradduk is alleged to have killed can't tell her side of the story, and the building she entered with him has burned to the ground. But Perry is making connections to a wave of arson that struck Cleveland seventeen years ago--fires that lit up the dark secrets of two families, a local powerbroker, and at least one crooked cop. Now Perry and his partner can see ties between the past and present, between innocents and criminals--and sirens that keep playing...