When Elias Moor was discovered dead inside a locked room above a warehouse on Mill Street, the police initially believed they were dealing with suicide.

Cryer disagreed.

The room was locked from the inside.

The key was lying on the desk.

There was one window, but it opened onto a sheer brick wall.

Nothing else appeared disturbed.

Cryer examined the floorboards.

Near the fireplace was a narrow line of dust where something heavy had been dragged.

He followed it to the wall.

There, concealed behind a hanging coat, was a small service hatch leading into the adjoining warehouse.

The hatch had been painted shut but someone had recently opened it.

Cryer questioned the warehouse manager, Alfred Pike.

Pike denied knowing it existed.

That afternoon, and during questioning, Cryer found fresh paint beneath Pike's fingernails.

Pike confessed before sunset.

It transpired that Moor had discovered Pike stealing money from the warehouse accounts.

Pike entered through the service hatch, struck him and staged the room to appear impossible to enter.

The locked door had never been the mystery.

It had been the distraction.