Think you’re observant enough to solve these tough detective riddles? Let's find out.
12 Detective Riddles Only the Smartest People Can Solve
Updated on Jun. 09, 2025
Empty cell mystery
Andy is put in a cell with a dirt floor and only one window. The window is too high for him to reach. The only thing in the cell is a shovel. He won’t be able to get any food or water and only has two days to escape, or he’ll die. Andy can’t dig a tunnel because it will take him much longer than two days to do it. How will Andy escape from the cell?
Empty cell mystery answer
Andy has to use the shovel to create a pile of dirt under the window so he can climb up onto it and escape from the cell.
Poisonous drinks
Marissa and Juliana went out for drinks together. They ordered the same drink. Juliana was really thirsty and finished five in the time it took Marissa to finish one. The drinks were poisoned, but only Marissa died. How?
Poisonous drinks answer
The poison was in the ice. Since Marissa’s ice had time to melt, she was poisoned, but Juliana wasn’t.
Suspicious suicide
A dead female body lies at the bottom of a multistory building. It looks as though she committed suicide by jumping from one of the floors.
When the detective arrives, he goes to the first floor of the building, opens the closed window and flips a coin toward the floor. He goes to the second floor and does the exact same thing. He continues to do this until he gets to the top floor of the building.
When he comes back down, he states that it was a murder and not a suicide. How does he know that?
Suspicious suicide answer
She couldn’t have jumped from any of the floors because when the detective went to each floor, all of the windows were closed. The coin flip was a red herring, turning this simple riddle into an extra-tricky puzzle.
Love at a funeral
A girl is at the funeral of her mother. She meets a nice guy that she didn’t know, who was also at the funeral, and they hit it off. She was busy at the funeral and didn’t have time to ask him for his number before he left. She tried really hard to track him down, but no one knew who he was or how to contact him. A few days later, her sister dies, and the police suspect it to be a murder. Who killed her sister?
Love at a funeral answer
Admittedly, this is something of a trick question. See, the girl killed her sister. She was hoping that if someone else in her family died, the man she met at her mother’s funeral would show up again. Did you see that coming?
Stolen ring
Nicole went to the police to report that someone had stolen her vintage ring. When the police got to her house, they noticed glass on the grass beneath a broken window, a total mess inside and dirty footprints on the carpet. But there were no other signs of a break-in.
The next day, the police arrested Nicole for fraud. Why?
Stolen ring answer
As soon as the police got to the “crime scene,” they knew that Nicole had most likely staged the break-in. The glass from the broken window was all outside of the house, meaning that it had been broken from the inside.
Thief at sea
A Japanese ship was leaving the port and on its way to open sea. The captain went to oil some parts of the ship. He took his ring off so it wouldn’t get damaged. He left it on the table next to his bunk. When he returned, it was missing. He had suspected three crew members could be guilty and asked them what they had been doing for the 10 minutes that he had been gone.
- The cook said, “I was in the kitchen preparing tonight’s dinner.”
- The engineer said, “I was working in the engine room, making sure everything was running smoothly.”
- The seaman said, “I was on the mast correcting the flag because someone had attached it upside down by mistake.”
The captain immediately knew who it was. How?
Thief at sea answer
It was clearly the seaman. It was a Japanese ship, and the Japanese flag is white with a single red dot in the middle. It can’t be hung upside down.
Murder at school
On the first day of school, someone murdered a history teacher. There were four people at the school that the police suspected had done it: the landscaper, a math teacher, a basketball coach and the principal. These were their alibis:
- The landscaper said he was outside mowing the lawn.
- The math teacher said he was giving a midyear test.
- The basketball coach said he was running practice drills with his players.
- The principal said she was in her office.
After hearing their alibis, the police arrested the killer immediately. Who killed the history teacher, and how did the police know?
Murder at school answer
The math teacher killed the history teacher. He claimed that he was giving a midyear math test, but it was the first day of school.
Poisonous pills
A serial killer kidnapped five different people and sat them down, each with two pills in their hand and a glass of water. He told them each to take one pill but warned them that one was poisonous and the other was harmless. Whichever pill the victim didn’t take, the serial killer would take. Every victim somehow chose the poisonous pill and died. How did the serial killer get them all to take the poisonous pill?
Poisonous pills answer
Neither of the pills was poisonous. The poison was in the water that all the victims used to swallow their pills. Were you tricked? Pay close attention to the wording of the riddle: The serial killer warned them one was poisonous, but that doesn’t mean he was telling the truth.
Honeymoon mystery
A couple went to Hawaii for their honeymoon. Unfortunately, the husband returned home alone because his wife had died in a horrible boating accident. The police contacted the travel agent who booked the trip for the couple and then arrested the husband for murdering his wife. How did they know he did it?
Honeymoon mystery answer
The travel agent revealed that he had booked a one-way ticket for his wife. This is what’s known as a lateral-thinking puzzle, and it’s a great way to stretch your mind and challenge yourself to think outside the box.
Science case
A chemist was murdered in his own lab. The only evidence was a piece of paper that had the names of chemical substances written on it. The substances were nickel, carbon, oxygen, lanthanum and sulfur.
Only three people came by the chemist’s lab on the day of the murder: fellow scientist Claire, his nephew Nicolas, his wife and his friend Marc. The police arrested the murderer right away. How did they know who it was?
Science case answer
There was a very obvious clue on the piece of paper. As a visual puzzle, this riddle is easier to solve, so write it out! If you combine the abbreviations of the chemical substances on the paper, you’ll get a name: Ni-C-O-La-S.
Recorded last words
A man was found on the floor dead with a cassette recorder in one hand and a gun in the other. When the police arrived at the scene, they pressed play on the recorder. It was the man’s voice. He said, “I have nothing else to live for. I can’t go on,” followed by the sound of a gunshot. After listening, the police knew that this was a murder, not a suicide. How?
Recorded last words answer
If the dead man had killed himself, he wouldn’t have been able to press the rewind button on the cassette recorder.
Guilty in court
A woman is in court for killing her husband. She says she isn’t guilty and that she dearly misses him. In the closing statement, the woman’s lawyer stands up and says, “Her husband is just missing, not dead. Everyone, look toward the doors. He’s going to walk in through them in about 30 seconds.”
The entire jury stares at the doors, waiting for this woman’s husband to walk in. The lawyer and the woman stare at the jury.
The lawyer concludes her closing statement by saying, “See! If you were so sure she killed her husband, you wouldn’t be watching that door!”
The jury immediately gave a guilty verdict. Why?
Guilty in court answer
The woman was watching the jury and not the doors. She knew that her husband wouldn’t walk through them because she had killed him. If she had really missed him like she said, she would have been watching the doors.
Thought these were easy? Try to solve these tough riddles that very few people can figure out.
Why trust us
Reader’s Digest is known for our humor and brain games, including quizzes, puzzles, riddles, word games, trivia, math, pattern and logic puzzles, guessing games, crosswords, rebus, hidden objects and spot-the-difference challenges. We’ve earned prestigious ASME awards for our entertainment content and have produced dozens of brainteaser books, including Word Searches, Word Power, Use Your Words, Fun Puzzles and Brain Ticklers, Mind Stretchers, Ultimate Christmas Puzzles and more. Our 10 published volumes of Mind Stretchers were edited by Allen D. Bragdon, founder of The Brainwaves Center and editor of Games magazine. Read more about our team, our contributors and our editorial policies.
