[Gunma Ota: Parent-Child Stabbing] What Happened Between the Suspect and His Ex-Wife’s Mother and Brother… The “Mystery” Behind the Motive for the Attack Carried Out with Two Kitchen Knives

Stabbed in more than a dozen places, including her legs and chest…

Around 9:00 a.m. on September 29, suspect Riki Mihara (30) was transferred from the Maebashi Police Station of the Gunma Prefectural Police. Inside the police van, surrounded by the press, Suspect Mihara kept his head bowed, his eyes slightly open as he stared at his hands; his profile showed no expression.

Suspect Mihara was arrested on September 27. He is suspected of attempted murder for slashing the back of the head and back of his divorced ex-wife, Ms. A (28), with a kitchen knife at her parents’ home. Additionally, he is under investigation for the murder of Ms. A’s mother, Yuka Tezuka (52), an office worker.

“The incident occurred shortly after noon on September 25. Ms. A and her brother had been out since the morning, and it is believed that Ms. Tezuka was attacked sometime between approximately 6:00 and 8:00 a.m. and shortly after noon.

Suspect Mihara appears to have brought a kitchen knife from his home to Ms. Tezuka’s residence and entered through the unlocked front door. Ms. Tezuka sustained more than a dozen stab wounds to her chest, legs, and other areas; the cause of death was hemorrhagic shock.“A total of two knives, including one with a blade length of approximately 20 centimeters and bloodstains, were found near the scene, and both are believed to show signs of having been used in the crime,” said a reporter from the crime desk of a national newspaper.

When Ms. A and her younger brother returned home, they encountered suspect Mihara inside the house, at which point he allegedly slashed the younger brother with a kitchen knife on the back of the head and back. Because the younger brother resisted, suspect Mihara fled the scene. Subsequently, Ms. A called 110, and the incident came to light.A nearby security camera captured footage of Suspect Mihara fleeing barefoot. As a result of a search conducted by the prefectural police with a force of approximately 110 officers, he was located at a pachinko parlor in Takasaki City around 2:00 p.m. on the 27th and arrested.

Suspect Mihara reportedly made a statement to the effect that “I prepared a kitchen knife and went to the scene to kill Mr. Tezuka and his eldest son.” He has admitted to the charge of attempted murder of the eldest son and has also hinted at his involvement in Mr. Tezuka’s murder.

The crime scene—Mr. A’s parents’ home—is located in a neighborhood where new and older homes are intermingled. It was a two-tone gray and beige single-family home that appeared to have been built relatively recently.

The Mysterious Relationship with His Ex-Wife

From the outset, reports had cited domestic violence and relationship troubles between suspect Mihara and Ms. A as the background to the incident.

It appears the two had been divorced at least as of March. On March 30 of this year, the two got into an argument, and Ms. A’s younger brother, who was present, called 110 to report the incident to the Tochigi Prefectural Police.

Additionally, on June 2, Ms. A ran into a neighbor’s house claiming, “My husband took my cell phone,” borrowed a phone, and reported the domestic violence to the Ota Police Station of the Gunma Prefectural Police. The prefectural police issued a verbal warning to Suspect Mihara. However, it appears the two continued to live together afterward.

On September 19, Ms. A sought advice from the Sano Police Station of the Tochigi Prefectural Police, where Suspect Mihara resides. At that time, she reportedly explained that Suspect Mihara had told her things along the lines of, “Which do you choose—your family or me?” and “I’ll kill your mother and brother, and then I’ll kill myself.”

“Ms. A decided to return from Sano City to her parents’ home in Ota City to care for her mother, Ms. Tezuka, who was ill. It is believed that she got into an argument with Suspect Mihara over this matter.

The Gunma Prefectural Police, having received information from the Tochigi Prefectural Police, called Mr. A on September 24—the day before the incident—and advised him to leave his parents’ home and seek shelter for his own safety, but Mr. A remained there. Meanwhile, he is said to have also stated regarding his issues with Suspect Mihara, ‘I don’t want this to turn into a criminal case’” (the reporter mentioned earlier).

However, the incident does not appear to be as simple as a husband committing a violent act after stalking his ex-wife to force a reconciliation. One crime reporter said , “There may have been a feud between Ms. Tezuka, her son (Mr. A’s younger brother), and suspect Mihara.”

“According to reports, it appears that Suspect Mihara continued to live at the Tezuka residence—the scene of the crime—even after his divorce from Ms. A. However, he reportedly fell out with Ms. A’s family, particularly her mother, Ms. Tezuka, and by around April, he had moved out of the Tezuka home to live on his own.

Ms. A was essentially living with Suspect Mihara, and the two were seen together even after police incidents in March and June. Perhaps the trouble began in September when Ms. A returned to her parents’ home to care for Ms. Tezuka.”

Crime journalist Taihei Ogawa had the following to say about this case:

“I believe this case is extremely complex. Although Ms. A was divorced, her relationship with the suspect had not been completely severed; there are indications that the relationship continued, such as the fact that they were still in contact right up until the incident. At this point, we do not know the reasons or the detailed circumstances as to why that relationship persisted.

I believe the police took the actions they deemed necessary at the time, taking into account Ms. A’s wishes and the circumstances at the time. They likely did not foresee this outcome. Since they were ultimately unable to prevent this serious incident, I think it is necessary to review their judgments and responses from that time going forward.”

What could have happened between Mr. Tezuka, Ms. A’s younger brother, and the victim?

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