Detective Harper stood in the quiet, dimly lit hallway of the old estate, her eyes tracing the brass key that had been left on the floor beside the victim's body. Margaret Baines, the reclusive heiress, was found dead in her study, an ornate letter opener lodged in her chest. It was a gruesome sight, but there was something about the key that nagged at Harper's mind.

Margaret's will had been locked away in a safe - one that only her estranged brother, David, knew the combination to. But when Harper asked David about it, he denied any knowledge of the key.

After hours of searching, Harper found a small hidden drawer in the victim's desk. Inside was a letter: The key was always meant for you, but I never trusted you enough to give it to you.

The detective realized the truth - David hadn't killed Margaret out of greed. He had done it out of desperation. The key wasn't meant for the safe; it was a key to a life Margaret had been hiding from everyone, one that David had been desperate to uncover. The true motive wasn't money - it was the secrets locked away in his sister's past.