Japanese police on Wednesday raided the house of a 26-year-old man suspected of stabbing to death 19 people and wounding dozens of others at a facility for disabled in a small town near Tokyo, Japan's worst mass killing in decades.
About half a dozen plainclothes police entered the home of Satoshi Uematsu, a former employee of the facility, as reporters and TV cameras stood by.
Uematsu was earlier sent from a regional jail in the town of Sagamihara, about 45 km (25 miles) southwest of Tokyo, to the Yokohama District Public Prosecutors Office in Kanagawa prefecture earlier in the day.
Video footage showed him smiling in the police car as it drove away.
Uematsu, who gave himself up to police on Tuesday after the attack, had said in letters he wrote in February that he could "obliterate 470 disabled people" and gave detailed plans of how he would do so, Kyodo news agency reported.
Uematsu was involuntarily committed to a hospital after he expressed a "willingness to kill severely disabled people", an official in Sagamihara told Reuters. He was freed on March 2 after a doctor deemed he had improved and was no longer a threat to himself or others, the official said.
The affair has shocked a nation where the crime rate is low and such mass killings rare.
It has also sparked debate on whether and how the system for involuntary commitment and aftercare broke down since Uematsu had previously made clear his intent to commit the crime.
“Involuntary commitment is done forcefully by the authorities ... If the time period drags on longer than necessary, it becomes a serious violation of human rights,” Asahi newspaper said in an editorial on Tuesday.
"However … there were warning signs before the incident," the paper added. “Was the treatment and outwatch of the man sufficient? It is vital to closely examine the system of support for the man and his family, and the contacts between the medical system and the police.”