This held true for my week with the homicide squad. It turned into a great story for me – but not for the three people who were murdered during the course of time I was riding with the squad.

The single story that influenced my writing more than any other came at the end of the week, in the last hour of my weeklong stay with the squad. I sat in the squad supervisor’s office, going over the last-minute details and questions before I would turn my pager in and go back to the newspaper to write the story.

Sergeant George Hurt was tired – he and his detectives had chased three murders in five days. Sitting at his desk, he took off his glasses to rub his eyes. When he dropped the glasses on his desk I noticed that the earpiece had a deep groove cut into it. It was like spying a diamond in the sand, for I knew exactly how that groove had gotten there.

During the week I had watched the detectives at work, I had seen Sergeant Hurt take off his glasses on numerous occasions. Invariably, he hooked the earpiece in his mouth so his hands were free. At the murder scenes I had seen him approach the victim’s body and take his glasses off, always hooking them in his mouth. These were solemn moments. He was observing the victim as a detective but there seemed to be something else going on as well. A sort of communion, or secret promise. It was not something he would talk to me about when I asked.

But now I saw the earpiece and I knew something. I knew that when he hooked his glasses in his mouth, his teeth clenched so tightly on them that they cut into the hard plastic of the earpiece. It said something about the man, about the job, about the world. It was a telling detail that opened up a window into this man’s life. It said all that needed to be said about his dedication, motivation and relationship to his job. It was the most important thing I had seen in a week of seeing things I knew were important and vital to me.

I instinctively knew that as a writer I had to look for this. From now on I had to find the telling detail in all the people I wrote about, whether it was a crime story for a newspaper or a novel about a detective. My life as a writer had to be about the pursuit of the telling detail. If I was going to be successful, I had to find Sergeant Hurt’s glasses over and over again in my stories.

At the time, I was just beginning to write fiction. I was working on it at night, not telling anyone. I was experimenting, learning. It would be another five years before I got anything published. But the lesson learned in Sergeant Hurt’s office would see me through. Years earlier I had left the detective bureau feeling misunderstood and wronged. I now left feeling like a man with a mission, and a clear path toward completing it.

The moments didn’t stop then. They kept coming. I was lucky. I was blessed. I decided to shift my life, to move three thousand miles to the place my literary heroes had written about. On the day I arrived in Los Angeles I sat in a newspaper editor’s office being interviewed for a job on the crime beat. He tossed me that day’s edition of the paper. The day before, there had been a big crime, a bank heist in which the thieves had gone into the city’s labyrinthine storm water tunnel system to get beneath the target bank before tunneling upward. The editor, testing me, asked me how I would do a follow-up on the story. My answer that day passed muster and I was hired. A few years later I would answer with my first published novel, a story that took the bank heist and the tunnels and turned it all into fiction.

Moments. They kept coming. As a reporter in Los Angeles you don’t go out to every murder – there are too many and the city’s too spread out. You pick and choose. Sometimes it is chosen for you. One morning an editor called me and told me to swing by a murder scene on my way into the office. Just like that, like I was picking up coffee on the way into work. He told me the murder was on Woodrow Wilson Drive in the Hollywood Hills. I went as instructed and got the story. I also got the place where I would put the home of the fictional detective I had secretly begun writing about. A place where he could live and have a view of the city he helped protect, where he could go out on his back deck and take a reading, feel the pulse.

Nothing was lost. All experiences went into the creative blender and were eventually poured out as something new in my fiction. A story about a man found in the trunk of his Rolls-Royce became a novel about a man found in the trunk of his Rolls-Royce. Stories about cops put on trial became a novel about a cop put on trial.

It wasn’t only the cops I drew from. It was the killers, too. The first murder story I ever wrote was for the Daytona Beach News-Journal. It was a basic body-foundin-the-woods piece in 1981. But later that body would be connected to one of Florida ’s most notorious serial killers and I became fascinated by what the cops I knew considered the ultimate kind of evil.

Christopher Wilder was another serial killer. I wrote about him at length and for a time it seemed that he took over my life. As he crossed the country in a desperate effort to elude authorities, I think I took on the same mix of urgency and dread those chasing him felt. It seemed that each day a new woman was abducted or another body was found. It was a big story, perhaps the biggest of my career, but it was an awful story just the same.

Sometimes the killers called me. The phony hit man who was convicted of killing and burying his wife called from jail to say I had been too harsh on him. And then there was Jonathan Lundh, the killer the police feared fit the profile of a serial killer. He was smart, articulate and manipulative. He was also angry at women. The cops went all out to convict him of the one killing they knew about for sure. Lundh used to call me from jail all the time. Not just to protest his innocence, but to manipulate me, to try to find out what the cops were saying to me, what other killings they were telling me about. I remember hanging up the phone each time and feeling lucky that we were separated not only by the phone line but by the concrete and steel of the jail as well. No person I have ever spoken to in my life was creepier than Jonathan Lundh.

It took all of these moments for me to be able to do what I do now. My experiences with cops and killers and days on the crime beat were invaluable to me as a novelist. There could not have been the novelist without there first being the reporter on the crime beat. I could not write about my fictional detective Harry Bosch without having written about the real detectives first. I could not create my killers without having talked to a few of the real ones first.

Not all of the moments saw print in newspapers or in this collection. Not all of them could be written about. I remember one night at a Los Angeles crime scene where I was working backup to another police reporter. It was his story and I was there to help out if it turned into something big. We were standing outside the yellow tape and waiting with many other reporters for the detectives to come out of a house where four people had been found dead. It was all we knew. Four dead. Some were children. We were waiting to see which way the story would go.

I moved down the tape, away from the other reporters. I was hoping to get a private audience because I knew some of the detectives in the house. That’s what reporters do. They try to get something for themselves, something nobody else has. You stay on the beat long enough and you get to know the detectives. It gives you an edge.

When the detectives finally came out of the house I waved to the one I knew best. He came over and we spoke privately while the other reporters circled around the other investigators. The man I spoke to was a detective I had spoken to hundreds of times on prior cases. He was a good and tough detective in my estimation. I had never seen him show much emotion, not even when I watched him at cop funerals. There were details of his personality I was already using for my detective Harry Bosch.