TOKYO -- A Japanese man police say confessed to killing and dismembering nine bodies found in his apartment was handed over to prosecutors for further questioning Wednesday as more chilling details emerged.

The questioning by prosecutors is a procedure before formal indictment. So far, Takahiro Shiraishi, 27, only faces a possible charge of abandoning bodies, but police are expected to seek murder and dismembering charges.

Police arrested him Tuesday after finding the eight female and one male bodies in cold-storage cases, covered with cat litter and hidden in his apartment in Zama, a city southwest of the capital. Police say Shiraishi confessed he tried to hide the evidence.

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Police found the bodies while searching for a 23-year-old woman who had disappeared after exchanging Twitter messages with Shiraishi. They are working to identify the victims, saying she might be among them.

The gruesome case captured attention in a country known for public safety, topping news with reports that showed the building where the suspect lived in a small studio apartment.

On Wednesday, media reports quoted investigative sources as saying Shiraishi started killing as soon as he moved into his apartment in late August. His first victim was a woman whom he got in touch via Twitter, offering to assist her suicide wish, then killed her boyfriend to silence him, according to media reports, including NHK public television. They say Shiraishi also used similar tactic to kill seven other women.

A police official who spoke to The Associated Press on Tuesday said a toolbox and saw found in Shiraishi's apartment may have been used to dismember the bodies. Online descriptions of the apartment building indicate it had a plastic-sealed "unit bath" and he allegedly dismembered the bodies there.

Reports said the missing woman got in contact with Shiraishi via Twitter, seeking a partner for a suicide pact and saying she was afraid to die alone. The two were recorded by security cameras walking together outside of train stations near her apartment and the suspect's apartment, the reports said.

He told police his motives were money and sexual abuse, Japanese media reported Wednesday, but police refused to confirm the reports to AP.

Japanese police release information only through limited official statements or through news conferences that are exclusive to journalists in the police press club.