TL;DR: Plant one or more clues early, before a crime has happened, or late, just before the reveal.

When Ms. Sleuth finds the dead body (as she so often does) along with lots of clues and maybe a red herring or two, readers will pay attention to these clues and use them to try to solve the mystery alongside Ms. Sleuth. But what if a clue gives away the ending?

Whatever you do, don’t have Ms. Sleuth tell readers about the clue after she’s solved the crime. Not only is it not fair, but you may also have some angry reviews!

Instead: Plant the clue early or at the last possible moment.

First sneaky tip: Plant a clue before the crime is discovered.

Planting a clue early is one of the best ways to insert an obvious detail into your story and have your readers slip right past it.

Spoilers ahead!

In The Murder at the Vicarage, Agatha Christie plants a subtle clue when one character comments on Colonel Protheroe. While foreshadowing the Colonel’s murder, one character states, “No wonder his first wife left him.” The clue is in the parson’s wife’s response: “I don’t see what else she could do.”

You see, his second wife comes up with an alternative to leaving him–murder!

If this conversation happened after the murder, most readers would jump to the (rightful) conclusion that his current wife is the murderer.

When to use this too-early-to-be-noticed technique?

  • You want to be overlooked because it’s too obvious.
  • More clues will come later that are connected–this clue is meaningless without the later ones.
  • Separating clues in your story makes them easier for the reader to miss.

Second sneaky tip: Plant a clue right before a big reveal.

In the BBC series, Sherlock, the writers do a brilliant job of this in His Last Vow (season 3, episode 3).

Early in the episode, we learn that a woman who seems important to the plot (did you know characters can be red herrings?) wears a certain perfume. Moments before the big, shocking reveal, Sherlock smells the perfume in the room. John Watson says, “Mary wears it.” Sherlock says, “No, not Mary–someone else.” (Or words to that effect).

Sherlock turns the corner only to find… Mary.

This clue (the brand of perfume Mary wears) only works (IMHO) because the space between the clue and the reveal (Mary is about to murder someone) is so short.

  • If we knew what perfume Mary (and the red herring) wore earlier, we would have known it was important, and we wouldn’t have been surprised at the reveal.
  • If we weren’t told about Mary’s perfume before the reveal, we would have felt cheated and manipulated.

So when to use this last-minute just-before-the-reveal clue?

  • When your clue gives away too much AND
  • The clue is critical for the reader to have a chance at guessing the truth.

Have you seen examples of clues showing up before a crime has been committed or clues revealed only moments before the truth comes out?