A banker was found murdered in his office on a Sunday. The building was strictly locked, and only the CEO, the head of security, and the janitor had keycards. The security log showed no keycard swipes at all on Sunday. Detective Drake arrested the head of security. How did Drake know?
No keycard swipes
If no keycard swipes occurred on Sunday, the killer had to be someone who could bypass the electronic system entirely, or the security system was manually deactivated from the inside control room by the head of security.
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: Medium. More like this: Detective riddles with answers or try Truth & Lie Island for a different kind of puzzle.
More detective riddles
A priceless golden statuette vanished from a locked vault. Three people had access codes: the director, the treasurer, and the security chief. The vault door showed no signs of forced entry. The director claimed she was asleep. The treasurer claimed he was at a midnight diner. The security chief claimed he was reviewing camera footage. The detective arrested the security chief. Why?
Detective Reyes questions five witnesses about the order they reached the museum door. Aria reached the door before Iris. Iris reached the door before Carmen. Hugo reached the door before Aria. Jonas reached the door before Hugo. Who reached the door third?
An antique pocket watch stopped ticking precisely at 8:15. The owner was found dead at noon. The coroner stated the watch had been deliberately damaged by a tiny hammer blow to the internal gear. Who damaged the watch?
A priceless ruby necklace was stolen from a locked hotel suite. The maid found the door unlatched and the safe open. The guest claimed he put the necklace in the safe before going to sleep and woke up to find it gone. Detective Patel noticed the guest's heavy winter boots were caked in dry mud, even though it hadn't rained or snowed in the city for weeks. What did this reveal?
An art collector reported a forged painting hanging in his gallery instead of the original masterwork. Three suspects had access: the curator, the cleaner, and the framer. The curator wore white cotton gloves. The cleaner wore rubber dish gloves. The framer wore leather work gloves. Which suspect left behind smudge marks of wet oil paint on the frame?
Inspector Lane investigated a counterfeit painting ring operating out of an old barn. Inside, she found a master forger working frantically on a canvas depicting a snowy winter landscape. Canvases, tubes of oil paint, and brushes were everywhere. Lane pointed to a calendar on the wall showing the current date as July 12th and immediately confiscated the unfinished painting as primary evidence. What gave away the forgery operation's timeline?