The police are zeroing in on the victims of Japan's most gruesome serial murder case in recent memory, adding a female high school student from Gunma Prefecture to the potential list, investigative sources said Sunday.

More than a week after nine dismembered bodies were allegedly found in a sex industry tout's apartment in Zama, Kanagawa Prefecture, police are still compiling a list of potential victims.

In addition to the Gunma girl, investigators suspect a man and a woman from Kanagawa Prefecture could be among the victims. Their butchered bodies were discovered in seven cooler boxes in the 27-year-old man's apartment, they said.