One of my writer communities recently had a discussion on how much police procedure an author needs to know to write a convincing book. I think the answer depends on whom you wish to convince. If you want to sell your authenticity to real cops, then you’d better get every last detail right. If you want to sell your story to the average reader, then accurate legal procedure may actually get in the way.

I’m an avid consumer of true crime, and I marvel at the strange coincidences or jaw-dropping twists that you would have a hard time putting in work of fiction. For example, in one old case, Massachusetts cops visited a suspect’s apartment to ask him about a murder, only they find he wasn’t at home. They left their card in the door with instructions to get in touch, but surprisingly, the murderer instead skipped town. The cops never followed up because this guy was just one of many possible leads at the time. He was eventually apprehended in Pennsylvania after committing a few more homicides.

“We just didn’t get around to it” is not a plausible excuse for most readers, despite it being a very real problem for actual law enforcement officers who must balance competing cases.

Real-life cops must often wade through red tape and deal with budget restrictions that would bog down a novel. A sprinkle of bureaucracy can add realism, but readers don’t want to sit around with your hero or heroine while he/she waits months for a DNA result. Or maybe the result never comes at all. In Massachusetts at the moment, there is a terrible shortage of qualified medical examiners. This means that many bodies are only receiving a cursory external examination, and follow-up tests may take months or never occur at all.

Or consider the bizarre tale of Sheila Davalloo, who somehow convinced her husband Paul to move to a hotel on the weekends so that she could carry on with her lover. Later she blindfolded Paul and stabbed him several times, all the while insisting she wasn’t actually trying to kill him. And he believed her! Prosecutors had to lay a lot of groundwork for the incredulous jury to accept Paul’s version of events, especially because he was a medical researcher earning a doctorate at Columbia University at the time. If he were a fictional character, we’d expect him to be smart enough to see through his wife’s outrageous lies.

Then there was the part where Sheila acted as her own attorney at trial, leading to a strange moment where she questioned Paul on the witness stand about who really committed her attack. “You…you stabbed me,” he said. Did she really think he was still in the dark after his open-heart surgery?

Truth is stranger than fiction, but it also moves a lot more slowly. It can take years to arrest and convict a murderer, even if the cops know who the guilty party is right away. Most mystery novels, in contrast, feature a case that is solved within days or weeks. If you’re going to tell a complete story in 300 pages, you have to pick up the pace. It’s important to get right what details you can. Beyond that, kindly readers will probably forgive you for fudging some of the finer points in favor of a compelling narrative.