My novel weaves back and forth between 1991 to present, but the query letter focuses on the present timeline, with a few references to the past. I'm not sure if I've been successful or if it's a muddy mess.
Dear Query Shark:
Heather Cole has a secret. When she was twelve, she killed her best friend.
Construction crews are about to dig up a field near her parents' house, and she has to find the evidence buried there before they do. More pieces of her past arrive in the mail, each one telling a different story. And someone's lurking outside her office. Someone who reminds her of the Red Lady.
Since she "got away with it" what evidence is there? In other words, did Heather get away with it, or just avoid suspicion. Two very different things.
You might consider leaving the question of whether the Red Lady is real more ambiguous. Ambiguity is good in a novel like this. Given the next paragraph, it seems like there IS ambiguity already!
As much as Heather would like to believe the Red Lady's real, she knows better now, which makes her a cold-blooded murderer. Unless someone's been playing a masterful game of manipulation all along. Even with all her experience in the workings of the human mind, the search for the truth might drag her into a labyrinth of lies she can't escape.
THE LIAR'S TRUTH, a thriller that weaves back and forth between the present and the summer of 1991, is complete at 83,000 words.
This is a very good way to handle the two timelines. Just from reading this query I can intuit that 1991 is the year Heather killed her best friend.
This is not a thriller. This is psychological suspense. And that's good for you, cause thrillers are harder to sell right now.
I'm the author of THIS (Small Publisher, 2016), a novel, and THAT (Small Publications, 2015), winner of the This is Horror Award for Short Story Collection of the Year. My short fiction has been nominated twice for a Bram Stoker Award, reprinted in The Year's Best Dark Fantasy & Horror and The Year's Best Weird Fiction and published in in various anthologies and magazines, including Cemetery Dance Online, Nightmare Magazine, and Black Static.
Thank you for your time and consideration,
Have confidence in yourself. This isn't even close to a muddy mess.
I'd say make a few minor revisions and you're good to go.
And don't forget to put me on your query list. I'd read this.