Inspector Lane found a cryptic suicide note written on a dry-erase board in a locked office. The victim loved cats and kept a Persian cat in the room. Lane wiped away the text with a damp cloth and immediately opened a murder investigation. What did he realize?
The cat could not have written it
A dry-erase board note can be easily altered or written by anyone who had access to the room. If it was a suicide note written by a person, it wouldn't be on a dry-erase board which is meant for temporary notes, or rather: a dry-erase board message can be wiped clean, but more importantly, a locked room with no writing instrument other than a marker implies staging. Let's refine: A dry-erase board can be written on by anyone post-mortem, and the handwriting didn't match the victim.
About this riddle
Detective riddles are tiny mysteries. Look for the detail in the story that does not fit; it is usually the clue that solves the case.
Difficulty: Hard. More like this: Detective riddles with answers or try Truth & Lie Island for a different kind of puzzle.
More detective riddles
An antique dealer was found dead behind his counter, struck down by a heavy brass statue. The store was packed with heavy items, but the cash register was wide open and empty. Detective Ray noticed that despite the chaotic struggle, the brass statue and the cash register had no fingerprints, while every other item in the store was covered in dust and smudges. What does this indicate?
A jeweler reported that a massive emerald was swapped for a glass fake during business hours. Four people touched the gem that day: the appraiser, the clerk, the owner, and a customer. The appraiser used a jeweler's loupe. The clerk used cotton-gloved hands. The owner used a golden set of tweezers. The customer used his bare, freshly washed fingers. The detective immediately knew which one switched it. Who?
In a dimly lit study, a historian was shot. The prime suspect claimed he was reading a book in the dark corner of the room when he heard the shot, and that he didn't turn on a light because he preferred reading by moonlight. Detective Sterling checked the moon phase for that night and immediately arrested the suspect. Why?
A librarian was found dead at the front desk, a heavy dictionary dropped on her head. The security log showed only three visitors entered that afternoon: Mr. Book, Ms. Page, and Dr. Spine. Each person had a verified alibi involving reading in the stacks. Detective Reed noticed a small bookmark sticking out of the dictionary, placed neatly on page 404. Reed arrested the killer. Who was it?
An antique pocket watch was stolen from a locked glass cabinet. The thief left behind a single fingerprint on the exterior glass. The fingerprint database matched three regular visitors: a blind man who only touches items to read Braille, a toddler who was carried everywhere by his mother, and a woman wearing heavy leather gloves. The detective immediately knew who the thief was. Who was it?
During a blackout, an antique pocket watch vanished from a drawer. Three suspects were in the pitch-black room: Anna, who held a flashlight; Ben, who clutched a glowing smartphone; and Clara, who gripped a heavy iron poker. Detective Hayes instantly knew Ben was the thief. Why?

