1. Understand the mechanism of death.
Every human dies because the central nervous system gets unplugged. This happens in many ways, but primarily either the cardiopulmonary system stops, which tells the brain to shut down or the brain stops, which tells the heart and lungs to give up.
In reality, this is harder to accomplish than it sounds, and it's human nature not to check out without a fight. So people are actually hard to kill. A bullet to the head is effective, but stabbings, for instance, are time-consuming, difficult, and messy. Poisons are slow, strangling is tough, and folks just don't stand there while being axed. So when you write the "perfect murder scene," think about how realistically you kill your victim.
2. Understand the time of death.
I've read (and seen on the screen) moments in which the coroner/pathologist declares the victim dead at a specific time, such as 10:05 pm. Uh . . . no—not unless someone was there with a stopwatch. Many mortis factors are considered when estimating the time of death. Temperature is the biggie, followed by body mass.
A dead body will naturally adjust the temperature (algor) to achieve equilibrium with its surroundings and will display time-telling factors, such as muscle stiffening (rigor), blood settling (livor), color (palor), and tissue breakdown (decomp). The presence of toxins also affects body changes. Cocaine amplifies the mortis process, while carbon monoxide retards it. Be careful in getting your forensic guru to commit on specific time.
3. Understand scene access.
Crime scenes are tightly secured. Absolutely no one goes in unless they're necessary, and then they'll wear complete personal protective equipment (PPE) to avoid contaminating the scene or themselves. This business of a gumshoe detective in a trench coat, smoking a cigar and leaning over the body, doesn't happen. Neither does a fifteen-year-old sleuth tagging along to help solve the case.
4. Get the terminology right.
I see writers get basic terms wrong, and it's the little mistakes that seriously affect credibility. For example, calling a 9mm pistol a "revolver" or saying the body was "prone" on its back on the floor. So much is available through Internet searches or, better yet, having beta readers pick up on errors. Remember: check what you write.
5. Crime-lab results are not so quick.
Processing crime scene evidence is a cumbersome, frustrating, and time-consuming event. First of all, yours is not the only case the lab has, and it will sit in queue to get developed. You'll probably get bumped to the back of the bus by more urgent files and it could be months before your DNA profile comes in. And, no, a phone call from the scene to your buddy in the lab is not going to speed things up. He'd probably get canned for playing favorites.
6. Don't get creative with investigational aids.
Most writers fail to consider the multitude of resources used in criminal investigations. DNA is today's darling, followed by AFIS (the Automated Fingerprint Identification System). Don't just write in the usual things like forensic autopsies, toxicology, ballistic matching, and document examination. Expand your story by using informants, wiretaps, room bugs, and wires, polygraphs, undercover operators, police agents, hypnosis memory enhancement, psychological profiling, computer analyzing, satellite surveillance, and one that's a real bugger—entomology. Stay away from using psychics, though. I've never heard of a case in which psychic information was anything other than a wild goose chase. I think psychics are as toxic to a believable story as a "dream" ending.
7. Use the five senses.
The best page-turners happen when you connect with your reader's senses: sight, sound, smell, taste, and touch. This seems to be the key to pulling off the show-over-tell thing. I keep a little sticky note on the bottom of my screen to remind me to make the most of the senses in each scene—it sure helps in editing.
Smell is the strongest link to emotional connection. It's one thing to see gruesome photos of a gut-shot corpse, but once you've actually whiffed a maggot-crawling, gassing-off decomp, you'll never forget it. Try writing out that sock-puking stench. Show the detective dumpstering his $500 leather jacket because the putrefaction permeated the calf-skin pores, and dry cleaning it just made it stink worse. True story—happened to me.
8. Craft a believable dialog.
Be honest. Cops and crooks swear like sailors, and that's the reality of the crime world. And some of the most foul-mouthed friends I have are females.
There's a balance, though. If every fourth word is four letters, it'll get a little overpowering, but none at all is unrealistic. I read a prominent crime writer's best seller on a recommendation. I picked up right away that something wasn't quite right. Then I came to the part where a character had to use profanity—no way around it to be true to the character—and the author wrote it as 'F@#*!'. I quit reading and I'm sure others did too.
9. Create compelling characters.
Something that's as true as the fact that you're going to flush the toilet before bedtime—the best cops and crooks have vibrant personalities. And they're not entirely good or bad either. One of the Hell's Angels I know should be a stand-up comedian, and a fellow coroner, who looks like frump-woman, is like traveling with Yoda. She has a terrible drinking problem, though, and sleeps with her incontinent ferret.
10. Understand the science of story.
I can't stress this enough. There's very much a science behind storytelling as there is in doing autopsies. Why readers stay up—and can't put a novel down—is that writers work words that release endorphins in the reader's brain.
