A knife-wielding man killed at least 15 people and seriously wounded many others at a facility for the disabled in Japan on Monday night.
Japanese news agency Kyodo said police in Sagamihara, Kanagawa prefecture had arrested a suspect aged in his 20s.
Media estimates of the number of people injured in the attack varied from 20 to 45, with four of the injured reported to be in cardiac arrest.
Sagamihara borders the capital Tokyo and is the third largest city in the prefecture.
Japanese broadcaster NHK reported that the suspect carried out the attack at Tsukui Yamayuri-en, a facility for the disabled in Sagamihara, shortly after 2.30am local time and then turned himself in at the Tsukui police station at about 3am.
Former employee
The man is believed to have previously worked at the facility, which provides accommodation and day-care services and has a swimming pool, gym and medical clinic.
The Japan Times described the attack as one of Japan’s worst single-perpetrator mass murders in the postwar era.
A neighbour of the facility, in a mountain valley area south of Mount Takao, told NHK that the attacker had blond hair and wore black clothes.
Japanese newspaper Asahi Shimbun reported that the suspect was quoted by police as saying: “I want to get rid of the disabled from this world.”
Sagamihara is about 40 km southwest of Tokyo.
Additional reporting: Reuters