The knife found beside Arthur Clegg's body was spotless.

Witnesses had seen the killer flee only minutes earlier.

Cryer examined the stove and found a saucepan filled with boiling water.

The killer had washed the blade.

But beneath the saucepan was a blood-soaked cloth.

The murderer had used it to protect his hands from the hot metal.

The cloth bore the initials of Clegg's brother-in-law.

He confessed before the knife had even cooled.