"We'll know more after the lab boys arrive," Amy said. "For now, let's assume the judge did write those letters. What does that tell us about the killer's movements?"
Her father mulled it over. "The killer left the room before the judge died."
"Right. The killer certainly wouldn't have stood by and watched him write a deathbed message. He must have assumed the judge was dead. Now-- did the killer return to the scene later?"
"No," Harry said with confidence. "If he did, he would have seen the writing and wiped it off."
Amy made a face. "Not necessarily. The victim had blood on his finger. A luminol test would have shown blood traces on the wall, no matter how hard the killer wiped."
"Maybe," Harry half-agreed. "But so what? Does it matter if the killer came back or not?"
"Of course it matters. In fact, the way those letters are written tells me the killer did come back. It also tells me who the killer is."