The Vanishing Key

When billionaire Arthur Langley was found dead in his high-security penthouse, the first question wasn’t who—but how.

The steel door was locked from the inside. No windows were broken. The security cameras showed nobody entering or leaving.

Detective Jace Novak examined the key hanging from Langley’s neck.

“This key,” he said to his partner, “opens the vault. The one holding $10 million in diamonds.”

His partner frowned. “But the vault’s still locked.”

Jace smirked. “Not for long.”

He grabbed the key, opened the vault—and found it completely empty.

The realization hit him.

“The killer never left.”

A sudden noise from the dark hallway made Jace spin around, gun raised.