They looked at each other like two lovers who had been separated. The FBI guy was caught up so bad. After the execution he came back looking like he had lost his best friend. This guy fell into the abyss in my opinion. The mind of a murderer is a dangerous place to be, but getting into it is often as essential and effective a part of crime-solving as collecting forensic evidence.
Some people collect salt and pepper shakers.
The fetishist collects dead things. Though I've never understood salt and pepper shakers myself.