I’m proud to welcome my friend and fellow ITW thriller author Lisa Black to TKZ today. Lisa claims to have spent the happiest five years of her life in a morgue. Strange, perhaps, but true. In her job as a forensic scientist she analyzed gunshot residue on hands and clothing, hairs, fibers, paint, glass, DNA, blood and many other forms of trace evidence, as well as crime scenes. Now she works as a latent print examiner and crime scene analyst for a police department in Florida. EVIDENCE OF MURDER is her fourth published thriller.

I do not make a habit of taking my plots from real-live cases—it always sounded like a good way to get sued to me—but the germ of an idea for Evidence of Murder did come from a case I worked with the coroner’s office in Cleveland, Ohio. A woman who worked as an escort—quite legitimately, through an agency that could be looked up in the phone book—disappeared from the face of the earth after one final date.  She had a steady live-in boyfriend and an eight year old daughter. The story stuck in my mind for two reasons.

One, escorting (if that’s what it’s called) seemed like an odd way to make a living—at least to me, having been married long enough that spending every night with a different man sounds like an agonizing amount of work. Certain readers may be disappointed, but very little of the book refers to the victim’s job. For the most part it is mentioned only to point out that every person she encountered wrote her off as a brainless bimbo, including—at first—my main character, Theresa MacLean.

Two, it was one of those cases where the cops were positive they knew whodunit, but could not prove it. One huge disservice that the television shows do to the field of forensics is to insist that you can always find more evidence if you just look harder. Yeah, right. That’s like saying doctors could cure cancer if they really tried and obese people would be thin if they’d only eat less. Sometimes a clue (or a cure, or a solution) simply isn’t there. Sometimes cool things are there but may not be clues. I have a mental list of my real-life cool clues that never went anywhere. In one high-profile case where a mother of three was abducted from the parking lot of the local mall and later found assaulted and shot to death in her own van, I kept finding rabbit hairs dyed a brilliant cherry red. The family had only just bought the van and gave me every set of hairs, every coat, every piece of clothing they thought might have been in it. I asked the detectives to keep an eye out for some fun fur trim or a lucky rabbit’s foot (though those had fallen out of style by 1996). It never turned up. By the time we caught the killers, a year had passed. No red rabbit fur. Another time I was examining the raincoat of a murdered prostitute under ultraviolet light, looking for semen or fluorescing fibers. At one spot on this plastic raincoat a pattern leapt up—a crystal-clear design of stylized daisies, something that would have been popular during my childhood in the late 60’s or early 70’s. Obviously the raincoat had been up against something with fluorescent properties and, for some obscure chemical reasons I couldn’t begin to guess, transferred to the vinyl. In regular light, the pattern became invisible. I described it to the detectives but again, no bells rung. In forensics, contrary to what you see on TV, you have to make your peace with not knowing everything.

Sometimes clues are there but can’t tell you enough. Finding the hair of the victim in, say, the trunk of the suspect’s car might be very incriminating—if he says he never met the woman, it might be enough to convict him. If he happens to live with the woman, it means exactly nothing, since her hair is likely to be all over the apartment and easily transferred to items he might put in the trunk. Or she might have dropped it there while leaning over to take out the groceries. Or it might have fallen out when he transported her body to the dump site. There’s no way to tell. So I wanted to explore what happens when every physical clue Theresa finds simply leads her to a brick wall instead of some helpful revelation.

Do you use problems in your character’s workplace to further the plot, and how? After all, when your character’s profession relates to their process of detection, it’s more interesting when the day job doesn’t go as planned.

Visit Lisa Black on the web at http://www.lisa-black.com/