The Killer's Way to Leave Evidence

There are also shoe prints. We know the killer was wearing size 11 white running shoes. These were a type of shoe that were manufactured in South Korea. No shoes of this type and this size were sold in Japan because what the police did after this was to track down the provenance of any of these items. They analyze the poop. They saw that the murderer in the 24 hours leading up to the crimes had eaten string beans and sesame seeds. There's no shortage of independent investigators who will allege that there was incompetence or even corruption on the part of the Japanese police, but we see that they did digging that led to some pretty important breakthroughs.