Case #7: The One-Minute Alibi

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The One-Minute Alibi 

Late one evening, a small tech startup reported a missing prototype laptop containing unreleased software worth thousands.

The office had strict security. Every door used a keycard system that logged time of entry, but not how long someone stayed inside.

Here’s what the logs showed:

• 9:12 PM – Cleaning staff entered

• 9:47 PM – Cleaning staff exited

• 10:05 PM – Junior developer Leo entered

• 10:06 PM – Leo exited

Leo explained that he remembered forgetting his charger, rushed back in, realized it wasn’t there, and left immediately.

The manager insisted the laptop was still on his desk when he left at 6:30 PM.
There were no signs of forced entry, and no security alarms were triggered.

At first glance, Leo’s one-minute visit seems too short to steal anything.

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⏸ Pause & Think

If Leo didn’t have enough time to take the laptop, how did it disappear?

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✅ The Solution

The key detail isn’t the short visit, it’s what the system doesn’t record.

The logs only show when a card is tapped, not how many times a person enters using someone else’s card.

Leo likely entered earlier in the night, using a borrowed or unattended keycard, possibly from the cleaning staff, stole the laptop, and later tapped in and out for one minute to create a clean, misleading digital trail.

That one-minute entry wasn’t suspicious because it was short.
It was suspicious because it was unnecessary.

👉 Conclusion: Leo used the keycard system’s limitation to create an alibi.

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