Japan’s most reviled serial killer – a “cannibal nerd” who preyed on primary-school girls and drank their blood – has been executed in Tokyo.

The hanging of 45-year old Tsutomu Miyazaki brings to 13 the number of death-row inmates who have faced the gallows since last August: a pace that has provoked rising criticism of Japan’s new justice minister, Kunio Hatoyama.

But even amid growing public discomfort in Japan over the continued use of the death penalty, the hanging of Miyazaki raised very little in the way of condemnation.

His crimes may have taken place two decades ago, but the mere mention of Miyazaki’s name remains sickening for many Japanese. Unrepentant throughout his long run of trials and appeals, Miyazaki entered Japan’s public consciousness as one of the worst monsters the country had produced.

A voracious sexual predator, he kidnapped girls aged between four and seven years old, molested and murdered them. In some cases he ate parts of their bodies, in others he slept next to their corpses.

"The atrocious murder of four girls to satisfy his sexual desire leaves no room for leniency," Chief Justice Tokiyasu Fujita said in January 2006 when Miyazaki’s final appeal was thrown out and the death penalty handed down.

During his trial, Miyazaki sketched cartoons and often talked nonsensically. He blamed the outrages of which he was accused on a “rat man” alter-ego of himself – a character he also drew in cartoon for the court. Miyazaki’s defence rested in the argument of his lawyers that he was not mentally fit to be held responsible for his crimes. Court-ordered psychiatric examinations reached no unified conclusions.

His extraordinary appetites for pornography and manga comics gave the Japanese media its first example of a “killer geek”. Since then, it is a label that has been repeatedly applied to any murderer who appears to share those tastes – last week’s stabbing frenzy in Tokyo’s Akihabara electronics district was carried out by a man instantly branded in the public eye as a killer geek.

For his victims’ families and Japanese society at large, the Miyazaki killings were particularly shattering. Miyazaki began his spree of abductions and killings at the very peak of Japan’s 1980s economic bubble – a phase where the country’s mighty corporations seemed to hold the world at their feet and society boasted of its unique “harmony”.

Miyazaki’s hanging, which was carried out with the executions of two other convicted murderers yesterday, comes as the question of Japan’s continued commitment to the death penalty has come under close scrutiny. The country is to introduce jury trials for murder cases next year, and the question of how far ordinary Japanese will be happy to sentence criminals to death has yet to be resolved.

Prime Minister Yasuo Fukuda told reporters yesterday that there had been no discussion about halting the executions. “In Japan, the majority view is that capital punishment should be maintained, so I feel no need to change what we have continued doing until now.”