[1] His father was a day laborer who paid little attention to his children,[2] as a result of which Nishikawa lived predominantly with his mother, as his sisters would go to the San'in region in winter to earn money for the impoverished family.

[3] By the time he left the facility, his father had sold the family home,[4] forcing Nishikawa to search for work in Kyoto and Osaka, before returning to Tottori in October 1971.

[3] After being allowed temporary leave in October 1973, he worked for some relatives for a time, but eventually quit and filled his day by visiting pachinko parlors and movie theatres.

[1][5] He was later convicted of murder, attempted rape, theft, forgery and fraud, but was given an irregular sentence of 5-to-10 years imprisonment, as the prosecutor presiding over the case, Hideo Okano, believed that he would be rehabilitated in prison.

[1] On the night of September 10, Nishikawa, who had money problems, tried to rob an inn in Tottori, threatening the 58-year-old sister of the proprietor with a fruit knife, but was unsuccessful and soon arrested.

[10] On December 6, he went to his ex-convict friend's house where he befriended and talked with his wife, but at one point he grabbed the couple's 3-year-old child and threatened to kill it if the woman did not give him money.

[13] According to an employee at a bar in Kyoto, Nishikawa would approach them and ask that they turn off the neon lights and lock the door, as he and several supposed friends who wanted to browse the premises without being disturbed by others.

[16] On the following night, Nishikawa entered the "Kumi" snack bar, where he suffocated the 45-year-old proprietress Kumiko Masaki and stole 6,000 yen in cash, gift certificates and lottery tickets.

[17][18] That same night, while riding on the San'in Main Line, he threw out the murder weapon through the window and later disposed of her credit card at the Kinosaki Onsen Station.

[18] The Hyōgo Prefectural Police initially suspected focusing on a friend of Masaki, claiming that there was a strong possibility she had been killed after a drinking binge, but this theory was later ruled out.

[14] On that evening, he visited a snack bar in Matsue, Shimane Prefecture, requesting of the employee that she close the store as he did not want to "listen to other customers' bad karaoke".

[23] Her body was found in the afternoon of the following day, with two injuries to the neck and one to the left side of the chest, as well as strangulation marks,[18] with the Kyoto Prefectural Police determining that she had ultimately died of blood loss.

[22] On the morning of December 28, Nishikawa went to the "Nakama" snack bar, about 200 meters away from the last crime scene, where he stabbed 51-year-old Noriko Murakami with a knife before stealing 10,000 yen in cash.

[27][28] Meanwhile, Nishikawa himself first hid in the house of a former prison associate in Wakayama Prefecture,[30] from where he went on the Hanwa Line and travelled to Tennōji Station, where he stayed at an inn in Osaka under a pseudonym.

[34] Katsura would later claim that right before fleeing, her assailant said that he was the mysterious killer of the two women in Kyoto and had fled from Shimane, later leaving a newspaper article about his crimes on the front door.

[33] In response to this, the Osaka Prefectural Police began an investigation into the robbery and attempted murder, and after examining fingerprints the assailant had left behind, they were linked to Nishikawa's crime spree.

[33] On that same day, all inns and hotels in the country were put on lockdown, while police in Osaka, Kyoto and Hyōgo conducted stakeouts in an effort to finally capture the criminal.

[8] He was allowed to stay inside for the next 16 hours, during which he watched TV and played videogames with the woman's 7-year-old son, even giving her 10,000 yen to buy him a toy sometime in the future.

Since there were no clear provisions about having a single destination to try a suspect in a large-scale investigation, authorities took the unusual measure of charging him before the Osaka District Court, where the caseload was relatively light compared to others.

[43] Nishikawa was detained in Matsue Prison to await trial, but in April of that year, he attempted to commit suicide by repeatedly banging his head against the wall.

[47] The prosecutors countered his claims with the accumulating circumstantial evidence, including his blood type matching that found at the crime scene where Takahashi had been killed and witness statements.

[50] At the fourth session held on December 21, Hanae Katsura appeared as a witness for the prosecution, testifying that she had been attacked by him and expressing her belief that while he had not planned to kill her, she still wanted the defendant to be punished harshly.

A cross-examination was conducted at the Kyoto District Court on January 29, 1993, of a female employee working at the scene where Kyo Harada had been found, who testified about the situation inside the store before and after the crime, the presumed murder weapon, etc.

[52] The proceedings were concluded on May 29, with Judges Yoshiki Matsumoto and Keiichi Taniguchi recognizing that evidence indicated in the latter three murders pointed towards Nishikawa's guilt, but his motive remained unclear.

[54] In his final statement, he pointed out that while material evidence was lacking in the Masaki murder, the convict's own confessions as well as the results of the DNA analysis and the shoe imprints linked Nishikawa to the crime scenes.

In 2004, he began corresponding with American professor David T. Johnson, admitting to him in a letter that he was praying for the other death row inmates, and wished to be reintegrated back into society.

On June 7, 2005, Nishikawa (who had returned to his original surname)[60] and his defense counsel filed for a final appeal trial before the Supreme Court, with presiding Judge Kunio Hamada.

[23][60] Following the Supreme Court decision, Nishikawa and his team filed a total of 10 requests for a retrial,[61] frequently responding to questionnaires by anti-death penalty activists and claiming that he was innocent of the crimes.