Police served an arrest warrant for murder on Saturday on a man already being held on suspicion of dumping the body of a 13-year-old girl in Osaka Prefecture last month.
Koji Yamada, 45, is suspected of strangling junior high school student Natsumi Hirata to death on Aug. 13, as investigators have identified no other suspects from footage recorded by security cameras.
Local police decided to issue the warrant even though they have not yet established where the girl was killed or exactly how she was strangled to death.
However, the victim's DNA matched that in blood found in a car owned by Yamada.
Yamada has remained silent over the allegations, according to investigative sources.
The girl and Ryoto Hoshino, 12, who was with her the day they both disappeared, are believed to have been abducted together near Neyagawashi Station in the early morning on Aug. 13.
Hirata's body was found in a parking lot in Takatsuki on the night of Aug. 13, while Hoshino's body was found in a mountainous area of Kashiwara, 30 km south of the parking lot, on Aug. 21.
Yamada is also suspected of dumping Hoshino's body.
When the suspect was first arrested on Aug. 21, he told police that he had called the girl into his car but said it was a passenger who had beaten her and had then abandoned her body.