A 25-year-old construction worker was indicted Tuesday on charges of murder, robbery and abandoning the body of a female university student in Kyoto Prefecture, prosecutors said.

According to the indictment, Hiroaki Nishijima, of Kyoto's Yamashina Ward, went out on a date with Miki Iwabuchi, a 19-year-old sophomore at Kyoto Women's University, around 9 p.m on April 8. The two had become acquainted through e-mail.

Following a dispute, Nishijima strangled Iwabuchi around midnight and abandoned her body in the Uji River in Ujitawara, Kyoto Prefecture, the indictment says.

Police served Nishijima with another arrest warrant Tuesday afternoon in connection with another murder case.

They said Nishijima is suspected of also killing company worker Misako Miyauchi, 28. Her body was found May 8 in a river in Ayabe, also in Kyoto Prefecture.

Investigation sources said Nishijima has admitted killing Miyauchi and disposing of her cellphone in a bush in Kyoto. The phone was discovered after Nishijima told police where to find it, confirming his involvement in the case, the sources said.

Miyauchi also got to know Nishijima through e-mail. She left home May 5, telling her sister, "I'm going to meet an e-mail friend," police said.