Serial killer Tsutomu Miyazaki, executed Tuesday, was unrepentant of his crimes until he met his end on the gallows, according to media reports.

Known as the Otaku Murderer for his love of kiddy porn and slasher films, Miyazaki never showed remorse for his murder, mutilation and cannibalization of four girls aged 4 to 7 in the 1980s. Before the Supreme Court upheld the death sentence against him, Miyazaki wrote in a letter to Kyodo News that he had done "a good thing."

The court ruled that he was criminally responsible for his actions despite his severe personality disorder. It said he kidnapped and murdered the four girls from Saitama and Tokyo in 1988 and 1989 ''to satisfy his own sexual desire and appetite to own videotapes with footage of corpses.''

He never apologized to the families of his victims, instead suggesting that a cartoonish figure he drew called the "Rat Man" was responsible.

Details of his grisly crimes are shocking. Miyazaki apparently drank the blood of his victims and slept with the corpses. He also sent the remains of a slaughtered girl to her family to taunt them. He made crank calls to the other families.

His mental condition seems to have been related to a physical deformity, his misshapen hands. At school he was ostracized and friendless. His only close relation was his grandfather, whose death seemed to have prompted the killing spree.

Clinical psychologist Hirokazu Hasegawa said Miyazaki believed his crimes would resurrect the old man. Dr. Susumu Oda, a psychologist at Tsukuba University, was quoted as saying that Miyazaki's obssession with his videos "removed his consciousness from reality. Everything became an item to him, including people. The little girls he killed were no more than characters from his comic-book life."

Of Miyazaki's life in prison, defense attorney Junji Suzuki once said, "He's perfectly happy. He is allowed to read comic books all day."