Kanagawa Prefectural Police arrested a 19-year-old man on Thursday for allegedly murdering a 17-year-old local high school girl.

The man, from the city of Sagamihara in Kanagawa Prefecture, who claims to be a house painter, admitted to the allegations against him, according to the Kanagawa police. He is the girl¡¯s ex-boyfriend.

The girl, a high school third grader from the Kanagawa Prefecture city of Zama, adjacent to Sagamihara, was found lying on a riverbank in Sagamihara in a state of cardiopulmonary arrest around 1:50 a.m. Thursday. She was sent to a hospital and confirmed dead there.

The man is suspected of killing the girl, including by choking her, at a vacant site in Sagamihara around 9:50 p.m. Wednesday, according to the police.

The girl went out Wednesday afternoon, telling her mother that she would see her former boyfriend, but she did not return home. Her mother made an emergency police call around 11:50 p.m. that day.

The Kanagawa police found the girl lying at the vacant site after identifying her location from GPS data from her mobile phone.

The police will investigate the details to clarify the circumstances related to the incident and determine the cause of her death.

The site is about 100 meters from Shimomizo Station on the East Japan Railway (JR East)?Sagami Line.