Hokkaido police revealed Thursday that a 21-year-old woman, arrested on suspicion of murder, and her accomplices had used social media to extort a 17-year-old high school girl from the city of Rumoi before pushing her off a bridge to her death.

Authorities said that Riko Uchida, along with a 16-year-old boy, threatened the victim, Runa Murayama, on April 18 using a social media app.

The trouble allegedly began when Murayama used Uchida's photo without her permission on social media, which led to the extortion.

Police are investigating the sequence of events leading to the victim's death.

The suspects possibly coerced Murayama into transferring money or goods through electronic payment systems, according to police.

After extorting the victim, Uchida and the boy were joined by a 19-year-old woman and a 16-year-old girl. The four suspects allegedly confined Murayama inside a car from April 18 to 19.

The group then moved to the Kamui bridge in the city of Asahikawa. Uchida and the 19-year-old woman are believed to have pushed Murayama off the bridge, leading to her death.

While the four suspects had been arrested earlier on confinement charges, the two women were placed under arrest on murder charges on Wednesday. Those under 20 years of age are considered minors under the juvenile law, and as such are not named.

Police have not disclosed whether the suspects have admitted to the allegations.

Murayama’s family reported her missing in late April after being unable to contact her. Following a search, her body was found in late May in the lower reaches of the Ishikari River, with drowning identified as the cause of death.

The four suspects are acquaintances, and police are currently investigating their relationship with the victim.

Translated by The Japan Times