Third Suspect
A murder mystery where the only evidence is what the witnesses tell you.
Here's a quick guide on how to play Third Suspect, the free browser murder mystery and interrogation game. Every case starts the same way: a victim, three suspects, and two or three witnesses who had eyes on the murder window. One of the suspects is the killer. You have between fifteen and thirty minutes to find out which.
The play loop in five steps
- Read the case file– victim, suspects, scene.
- Interrogate the witnesses– ask anything; the AI-driven witnesses answer in character.
- Catch the lie– pin two quotes that contradict each other and flag the pair.
- Make your accusation– name the killer, the method, the motive.
- See the reveal– the truth comes out, points are scored.
1. The case file
When the round begins, read the victim's details, the three suspect dossiers, and the scene. Take a minute to form a first impression before you start asking questions. Every suspect has a motive you'd believe. Only one is the killer.
2. Interrogation
Pick a witness and ask them anything. Type your question in your own words – the witness answers in character, in real time. Their persona shapes the voice; their bias shapes the lies. Every witness is loyal to one of the suspects and will quietly cover for that person until you press them on the right detail.
Casual questions get casual answers. Pressing questions – “are you sure?”, “did you actually see her leave?”– surface the truths the witness has been holding back.
3. Catching the lie
When two quotes contradict each other – one witness saying a suspect was at the bar all night, another saying they walked back from the alley at eleven-forty – that's a contradiction. Pin both quotes, then flag the pair. The game scores every real contradiction you find. The biggest one points at the killer.
4. Accusation
When you're ready – or when the timer runs out – submit your accusation: suspect, method, and motive. Be specific. You don't get to guess again.
5. The reveal
After every detective accuses, the truth comes out. The reveal narration walks through what actually happened that night. Your final score combines the contradictions you flagged with whether you named the right killer for the right reasons.
Solo vs. with friends
Play alone with a generous question budget – every fact is yours to find. Or invite up to three friends with a share link: each detective gets fewer questions, but more eyes on the case. Cross-witness contradictions are much easier to spot when two players are comparing transcripts in a call together.
What makes a good detective
- Listen for specifics. Vague witness answers are often a tell.
- Press a witness with skeptical questions when something feels off. They often slip into the truth under pressure.
- Compare what two witnesses say about the same person. That's where the contradictions live.
- Don't accuse on the first thing that looks suspicious. The case is designed to have red herrings.
Frequently asked questions
What is Third Suspect?
Third Suspect is a free browser murder mystery & detective game for 1–4 players. Each case is a self-contained whodunit: interrogate the AI-driven witnesses, catch one of them lying about the crime, then accuse the killer by name, method, and motive before the timer runs out.
How long does a game take?
Between 15 and 30 minutes per case, depending on the tier. Standard cases run 15 minutes (3 suspects, 2 witnesses), Rich/Longer cases run 20 minutes (with extra suspects or witnesses), and Deep cases run 30 minutes (4–5 suspects, 3–4 witnesses).
How many people can play?
1 to 4 detectives per room. Solo play is fully supported with a generous question budget. Multiplayer is via a shared private room URL - each player gets fewer questions but more eyes on the case.
Do I need to install anything?
No. Third Suspect runs in any modern desktop or mobile browser. No signup, no app store, no downloads.
Is it free?
Yes. Free to play, no purchases, no ads.
Can I play with strangers?
Third Suspect is designed for friends on a Discord call who already trust each other. There’s no public matchmaking; you share a private room link with people you know. Strangers won’t be able to find your room without the code.
How is it different from Clue or Among Us?
No dice rolls, no cards, no random board movement (unlike Clue), and no votes or rounds of elimination among the players (unlike Among Us). The killer is set at case-design time; players reconstruct what happened from witness testimony, catch contradictions, and accuse the suspect they believe is guilty. The truth is fully recoverable from the testimony if you ask the right questions.