No Less The Devil by Stuart MacBride

It's been seventeen months since the Bloodsmith butchered his first victim and Operation Maypole is still no nearer to catching him. The media is whipping up a storm, the top brass are demanding results, but the investigation is sinking fast. Now isn't the time to get distracted with other cases, but Detective Sergeant Lucy McVeigh doesn't have much choice. When Benedict Strachan was just eleven, he hunted down and killed a homeless man. No one's ever figured out why Benedict did it, but now, after sixteen years, he's back on the streets again - battered, frightened, convinced a shadowy 'They' are out to get him, and begging Lucy for help. It sounds like paranoia, but what if he's right? What if he really is caught up in something bigger and darker than Lucy's ever dealt with before? What if the Bloodsmith isn't the only monster out there? And what's going to happen when Lucy goes after them?