A couple in their 20s were arrested Tuesday for allegedly disposing of the body of an 18-year-old high-school student in Yamanashi Prefecture near the capital after she went missing over the weekend, investigative sources said Tuesday.

The couple — Shohei Komori, 27, and his wife Izumi, 28 — living in Gunma Prefecture, have admitted under questioning to having dumped the girl's body and they also hinted that they killed her, the sources said, adding that the police will pursue a murder investigation.

Komori said he had become acquainted with Washino about two years ago through Twitter, and that his wife became jealous about their relationship, according to investigative sources.