How to Play Evidence Locker: Code-Breaking Tips
Evidence Locker looks simple: six symbols, a lock and a row of lamps. But the lamps hide a surprising amount of information, and players who learn to read them open lockers in half the guesses. This guide explains the rules in detail, walks through a complete Rookie Locker game step by step, and shares the strategies we use ourselves to reach the par on the harder safes.
The rules in one minute
- Every locker has a secret code of three, four or five symbols, chosen from badge, key, fingerprint, handcuffs, siren and magnifier.
- You place symbols in the empty row and press Check (or Enter).
- Each green lamp means one symbol is correct and in the right place. Each yellow lamp means one symbol is in the code but in another place. Dark lamps mean no match.
- Lamps are sorted green first, so they never tell you which symbol earned them.
- You have 8 to 10 guesses depending on the locker. Open it within the par for three stars.
There is no timer. A new random code is chosen every time you start a locker, so you can replay as often as you like.
Reading the lamps: what they really tell you
The single most useful fact is this: green plus yellow equals the number of your symbols that appear in the code, whatever their positions. The split between green and yellow only tells you about positions.
A few consequences that save guesses:
- All dark: none of your symbols is in the code at all. On a repeat locker that can wipe out several symbols at once.
- No green: every symbol you placed is in the wrong position. You learn where each one is not.
- Green + yellow = code length: you have found every symbol. Now it is only a sorting puzzle.
- Counting what is missing: on a no-repeat locker, if two of your three symbols are in the code, then exactly one symbol you did not use must be in it too.
A worked example: Rookie Locker
Locker 1 uses a three-symbol code made from four symbols (badge, key, fingerprint, handcuffs), and no symbol appears twice. Suppose the secret code is Key – Handcuffs – Badge. Here is how a careful game goes.
Guess 1: Badge – Key – Fingerprint
Result: 0 green, 2 yellow. Two of the three symbols are in the code, but none is in the place we put it. Since the code has three different symbols and only two came from this guess, the one symbol we left out, handcuffs, must be in the code. That is already a big step, and it only came from counting.
We also know the badge is not first, the key is not second and the fingerprint is not third. That leaves nine possible codes.
Guess 2: Key – Badge – Handcuffs
We choose a guess that could still be the answer: it uses handcuffs, keeps the key off position 2 and the badge off position 1. Result: 1 green, 2 yellow. All three symbols are right, so the code is made of key, badge and handcuffs. One is in place, two are swapped.
Only two codes fit everything so far: Key – Handcuffs – Badge (the key was the green one) or Handcuffs – Badge – Key (the badge was the green one).
Guess 3: Key – Handcuffs – Badge
Three green lamps. The locker opens in three guesses, one under the par of four. Had the answer been the other option, the fourth guess would still have hit par.
Strategy for no-repeat lockers (1–5 and 9)
- Open with different symbols in every slot. The game will not let you repeat symbols here anyway, so your first guess already tests three to five symbols.
- Use the count trick. With six symbols and a four-symbol code, exactly two symbols are missing. If your first guess of four shows three lamps, exactly one of the two symbols you left out is in the code.
- Move, don't replace, when green + yellow is full. Once all symbols are found, keep them and only change the order. Moving two symbols at a time makes it easy to see which move earned a green.
Strategy for repeat lockers (6–8 and 10–12)
From Double Trouble onwards a symbol can appear more than once, which changes the best opening.
- Open with pairs. A guess like Badge – Badge – Key – Key tests two symbols and also tells you how many of each there might be.
- Follow with the other pairs. On a six-symbol locker, a second guess of Fingerprint – Fingerprint – Handcuffs – Handcuffs covers two more. For example, if the code is Siren – Siren – Key – Badge, the first guess gives 1 green and 1 yellow, and the second gives no lamps at all: fingerprints and handcuffs are out completely, and the remaining symbols must come from badge, key, siren and magnifier.
- Remember the counting rule. A symbol only lights as many lamps as it appears in the code. Two badges in your guess and one badge in the code light one lamp, not two.
- Five-symbol safes need patience. The Detective's, Inspector's and Chief's lockers have thousands of possible codes. Two or three information-gathering guesses, followed by careful consistent guesses, usually reach par.
When to use the hint
The Hint button can be used once per attempt. It fixes one correct symbol in its correct place (shown with a green ring), and that slot stays filled for the rest of the attempt. The catch: an attempt that used the hint can earn at most two stars. Our advice is to save it for the five-symbol safes, or for when you have only two guesses left and several codes still fit. Because every new attempt draws a new code, you can always come back later for three stars without the hint.
Common mistakes
- Ignoring old rows. Every new guess should agree with every earlier row, not just the last one. Scan the board from the top before pressing Check.
- Reading lamps as positions. A green lamp on the left does not mean your left symbol is right. The lamps are sorted.
- Wasting the first guess on repeats in a no-repeat locker or, the other way round, testing five different symbols in a repeat safe where pairs give clearer answers.
- Guessing to "see what happens". A guess that cannot be the code may still give information, but it almost never beats a consistent guess for reaching par.
Controls
- Touch or mouse: tap a symbol at the bottom to place it in the next empty slot; tap a placed symbol in the current row to remove it.
- Keyboard: 1–6 place symbols, Backspace removes the last one, Enter checks, H uses the hint.
Where to go next
Opening all twelve lockers earns the Master Locksmith badge on your badges page. If you enjoy deduction, try Police Lineup, which uses the same "eliminate what it can't be" thinking with witness clues, and read our guide to detective games online for more logic techniques.