Motive, means and opportunity -- constructing a science-fiction mystery

So “By the Will of the Gods” was a first for me in many ways — my first sale, obviously; my first published science-fiction story; and also my first published mystery story.

Science fiction and mystery stories are similar in that there are certain rules both usually follow as conventions of their respective genres. Here I’m going to talk about some of the thinking that went into writing “By the Will of the Gods” as a mystery, and the special considerations involved with it also being a science fiction tale.

WARNING: SPOILERS AHEAD.

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STOP NOW IF YOU DO NOT WANT SPOILERS.

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YOU HAVE BEEN WARNED.

So with any crime, any investigator has to consider suspects who fit the trinity of motive, means and opportunity. Let’s examine each of these with the crime at the heart of “By the Will of the Gods,” starting in reverse.

Throughout the story, I established that the victim, Harrow, was an expert in both following targets and in spotting tails. He not only taught Hap these skills, but was a consultant for criminals trained in these skills, and was capable of guiding Hap into defeating these experts. At the same time, he was killed via knife, so his murderer somehow managed to get close to him and kill him. How would any potential murderer get that opportunity?

Since I established as a guideline in the story that it was virtually impossible for anyone to directly follow Harrow, that should suggest to the reader that someone indirectly followed Harrow. I established that there were cameras around the city, I established that Rusty could get files from city databases, and I established Rusty told Harrow when and where to meet him. As Hap noted, Rusty therefore knew where Harrow would start and stop his trip and roughly the time he would make his journey. Since I didn’t present anyone else with this knowledge (and believe me, had I felt comfortable making this story any longer than it was, I would’ve liked to include more suspects), Rusty seemed like the strongest — indeed, the only — suspect with the opportunity to commit this crime, or to assist the perpetrator.

Next, the means. Harrow was killed with an invisible dagger, a Pellucid Knife. (Since this is a science-fiction story, I wanted some kind of exotic means of death, but it’s difficult to come up with something new in either the science fiction or mystery genres. Personally, I like the concept of the Pellucid Knife, but I can see how others might find it silly. It’s the best I could come up with.) The detective, Bellows, gave clues that the wielder of the knife was inexpert, something that Hap later confirmed. (Thanks to bioanthropologist Constantine Mountrakis for tips on what inexpert cut wounds might look like.) At the same time, Hap and Palmer confirmed that the traditional owners of Pellucid Knives are expert wielders of daggers.

In the story, I had Palmer note that Harrow had many dangerous enemies. Hap also thought of Chase, who either might have wanted to commit the crime himself or hired someone else to do it. However, the inept nature of the attack suggested an amateur, not a professional. This likely ruled out many of the potential suspects Palmer had in mind, as well as anyone Chase might likely hire. Chase might conceivably count as an inept wielder of a knife, but I establish that he was off-world when Harrow was murdered.

At the same time, Palmer established that whoever killed Harrow prepared enough for the attack ahead of time to not leave any physical evidence behind except for the knife, which was presumably planted there to give police suspects in the form of Deltans. Hap and Palmer also established that a Pellucid Knife was usually only owned by Deltans, but that the killer was likely not a Deltan Blademaster due to the inept nature of the attack, so the killer had to find some way to get a Pellucid Knife before the assault. This suggested that the perpetrator had expertly prepared for the crime beforehand, yet was not actually skilled in the method employed. This doesn’t point at Rusty, but it doesn’t rule him out, either.

Finally, the motive. There is no obvious motive for Rusty to kill Harrow, as they were presumably friends, or at least collaborators. Hap eventually figured out that the motive behind this crime was in fact a previous crime, or rather many previous crimes.

A general rule in mysteries is that the writer has to “play fair” with readers — that is, the writer should make sure readers have everything they need to solve the mystery before the sleuth reveals the truth. The challenge in writing mysteries is to play fair while not making the killer’s identity blindingly obvious.

There are many tricks a mystery writer can use to play fair with readers. An invaluable guide for me in this regard was Hallie Ephron and Sara Paretsky’s “Writing and Selling Your Mystery Novel” — I cannot recommend that book highly enough. Anyhow, three principles I used were a) scattering clues throughout the story so as to not make it obvious they were clues; b) providing vital clues but then having the character focus on details that seem more important to him, in order to make the reader overlook the vital nature of the clues I just provided; c) presenting clues as something else.

One example of how I used that first method was how I slowly unveiled over time the details of how Harrow was killed and how difficult it would have been to kill him — first with Bellows, then with Hap reminiscing about attempting to follow Harrow, and finally with Hap’s talk with Palmer. Another way I used this method didn’t really have anything to do with the central crime of the story, but rather with what Harrow did for a living. I establish early on that Harrow doesn’t really seem to be a groundskeeper, and over time, I establish that he is covertly teaching Hap the kind of skills he would need for Harrow’s job, all in a very Mr. Miyagi “wax on, wax off” kind of way.

One example of how I used that second method was when Hap examined Harrow’s room. I had Hap see maintenance records for all of Nightingale; astronomical charts; and news reports from over the past decade. All these ultimately helped establish the crimes that Rusty committed before he killed Harrow. I even had Hap note that he was surprised that Harrow had the astronomical charts; since Harrow wasn’t religious (the primary religion of the story is obsessed with astrology and other methods of divining the future), why would he have these charts? And when Hap saw the news records, I even had him think of his parents’ deaths. But I hid the significance of these clues by mentioning other items Hap found, such as a bottle of booze, and details that he considered more important, such as crime reports — as Hap noted, these “gave me pause,” sneakily leading the reader to focus their attention on these details instead of the ones just mentioned, which is the kind of magician fool-the-eye trick so necessary in playing fair.

One example of how I used that third method was how I mentioned that Harrow died two weeks after he stood with Hap on the surface of Scrithel on the anniversary of the deaths of Hap’s parents. Mostly this episode established why Harrow meant so much to Hap. You have to squint to see it, but this episode was also designed to help readers reconstruct the series of events that led to Harrow’s murder. Harrow noticed that Hap liked standing on the surface of Scrithel on the anniversary of the deaths of Hap’s parents; Harrow went on to investigate the deaths of Hap’s parents; Rusty noticed someone accessing old records pertaining to his crimes; Rusty then went on to murder Harrow when he got the opportunity to do so. Since I established Rusty felt like he was in a hurry to kill Harrow, because Harrow was an expert investigator with dangerous confederates, that helped explain why the crime seemed like it was carried out with expert preparation but inept execution.

A final tricky aspect of writing this mystery was setting up the final confrontation between the sleuth and the perpetrator. The fact that Hap went to see Rusty near the end of the story should normally be a giant clue to readers that Rusty was the perpetrator, especially since my concerns about length meant that I didn’t really provide much in the way of other suspects. There were several ways I handled this. One was to have Palmer strongly suggest that Hap (and the readers) may never find out who actually killed Harrow. I also had Rusty tell Hap that he wanted to hear everything about Hap’s meeting with the Deltans as Harrow’s supposed friend, in order to make that final confrontation just seem like a friendly conclusion of some kind. I also, honestly, was as short-handed with clues as possible about the identity of Harrow’s killer to reduce the possibility that readers would guess it was Rusty — if I felt more comfortable with making the story long, I would have added more clues pointing at Rusty, as well as more red herrings pointing at other potential suspects.

So those were some of the critical mystery writing rules I used — the trinity of means, motive and opportunity, and fair play. Following those rules while also writing the mystery in a way to hopefully keep readers guessing until the end was difficult enough, but I also had to contend with writing the story as a science-fiction tale.

One of the keystones and problems with writing any SFF story is worldbuilding. Worldbuilding is necessary to some or even a large degree in such tales, but can also suck up way too much time, to the detriment of pacing and focus, among other things.

When it came to writing my hybrid science-fiction murder-mystery novelette, a problem I felt I faced was that the murder mystery guideline of playing fair added to a lot of bloat when it came to the SFF tendency to worldbuild. Since readers might expect that anything can happen in an SFF story, it made it difficult to play fair.

In my opinion, a SFF mystery has to lay down a lot of rules as to what likely is and is not possible in a story — e.g. is time travel involved, is phasing through a wall a possibility, are psychic abilities a thing, are there aliens with special abilities we have to think about, and so on. I feel the setting of “By the Will of the Gods” is a good mix of both hard and soft science fiction, but for the sake of playing fair, I tried to set up as much as possible the hard science of the setting — when I do describe fantastical things such as invisible daggers or pet dinosaurs, I point out what they can and cannot do. I also spend a lot of time describing physical activities such as fights, or escaping from restraints, or walking through a city, or struggling in microgravity, to help ground the mystery. (Hopefully, it also had the side-effect of making this fantastical world feel more vivid.)

There’s a reasonable argument one can make that I spent way too much time worldbuilding in “By the Will of the Gods.” I have to concede to this criticism to some degree. In my defense, it’s a really complex setting I created, so I felt like I had to spend a lot of time describing and explaining it. On a personal note, I really love this universe I created, and I think it’s cool enough to describe in great detail, and I think SFF often attracts readers who love worldbuilding, so hopefully many readers appreciated those details (tho I know there are definitely readers, including my own wife, who can find such worldbuilding tedious). And I love the somewhat meta aspect of this setting — how it makes Hap and Palmer imagine what-if scenarios, which is basically all of SFF. This meta aspect of this universe, and how it comments on SFF and fiction and writing in general, is very intentionally built into this story and likely all stories set in this universe.

Selfishly, I also intend to write more stories set in this universe, so by describing this universe in such great detail in “By the Will of the Gods,” I’m setting up stories further down the line. This is, in fact, a bad argument for including so much worldbuilding in this story. In my defense, I would argue that descriptions rich enough to make readers imagine more stories in a given setting inspire a feeling of wonder that many SFF readers in fact like. In fact, a few readers have actually messaged me saying that’s something they liked about “By the Will of the Gods,” so I’ll stand by this admittedly somewhat self-serving desire of mine.

So there you have it. Hopefully you (whoever you are) found this essay interesting, and perhaps informative if you want to write either a mystery, or science fiction, or a hybrid like I did.