A 19-year-old man was arrested Thursday on suspicion of killing a high school girl who was found lying on a riverbank near Tokyo early in the morning and was later confirmed dead.The man, a resident of Sagamihara in Kanagawa Prefecture, is believed to be a former boyfriend of the 17-year-old girl, Yura Sato, and police are investigating the circumstances surrounding her death.According to an investigative source, Sato, who lived in the adjacent city of Zama, went out on Wednesday evening and did not return home. Her family told police when reporting her missing that "she hasn't come home si…READ FULL ARTICLE