Tsutomu Miyazaki (宮﨑 勤, Miyazaki Tsutomu; 21 August 1962 – 17 June 2008) was a Japanese serial killer who murdered four young girls in Tokyo and Saitama Prefecture between August 1988 and June 1989. He abducted and killed the girls, aged from 4 to 7, in his car before dismembering them and molesting their corpses. He also engaged in cannibalism, preserved body parts as trophies, and taunted the families of his victims.

Miyazaki was arrested in Hachiōji in July 1989 after being confronted while taking nude photographs of a young girl. He was diagnosed as having one or more personality disorders, but was determined by authorities to be sane and aware of his crimes and their consequences. Miyazaki was sentenced to death in 1997 and was executed by hanging in 2008.

Miyazaki was dubbed the "Otaku Murderer" due to his extensive collection of anime, manga, horror videotapes and hentai as well as various other forms of pornography. This triggered a widespread moral panic against otaku in Japan, similar to the Satanic Panic in America.

Tsutomu Miyazaki was born on 21 August 1962 in Itsukaichi, Tokyo, the son of a wealthy family. He was born premature and had the rare birth defect radioulnar synostosis that caused his hand joints to be fused together, making him unable to bend his wrists upwards.^{[unreliable source?]} Miyazaki's family operated a regional newspaper company and were well known in Itsukaichi, where his grandfather and great-grandfather had served on the town council. Due to his parents being busy, he was mainly raised by his grandfather and an intellectually disabled man the family hired as a nanny.

Miyazaki was ostracized when he attended elementary school due to his deformity, and consequently kept to himself. He attended Meidai Nakano High School [ja] in Nakano, a prestigious high school associated with Meiji University, and was a star student until his grades began to drop dramatically. He was ranked 40 out of 56 in his class and did not receive the customary admission to Meiji University for students of the school. Instead of studying English and becoming a teacher as he originally intended, Miyazaki attended a local junior college and studied to become a photography technician.^{[unreliable source?]}

In the mid-1980s, Miyazaki moved back into his parents' house in Itsukaichi, sharing a room with his elder sister. Although his family was highly influential in Itsukaichi, he expressed no desire to take over their business. After his arrest, Miyazaki would say that what he really craved was "being listened to about his problems" but believed that his parents, more worried about the material than the sentimental, "would have not heard [him]; [he] would've been ignored". In the same confession, he said that by this period in his life he had begun to consider suicide. Miyazaki felt he only received support from his grandfather, to whom he was close, and was rejected by his two younger sisters.

In May 1988, Miyazaki's grandfather died, which served to deepen his depression and isolate him even further. In an attempt to "retain something from him", Miyazaki ate part of his grandfather's ashes. A few weeks later, one of Miyazaki's sisters caught him watching her while she was taking a shower; he attacked her when she told him to leave. When his mother learned of the incident and demanded that he spend more time working and less time with his videotapes, he attacked her as well.

Between August 1988 and June 1989, Miyazaki mutilated and murdered four girls between the ages of 4 and 7, and sexually molested their corpses; these crimes became known as the Little Girl Murders. He drank the blood of one victim and ate a part of her hand. These crimes—which prior to Miyazaki's apprehension were named the Little Girl Murders [ja] and later the Tokyo/Saitama Serial Kidnapping Murders of Little Girls (東京・埼玉連続幼女誘拐殺人事件, Tōkyō Saitama renzoku yōjo yūkai satsujin jiken)—shocked Saitama Prefecture, which had few crimes against children.