Following a fatal stabbing spree carried out by a lone male assailant at a care facility for people with disabilities in Japan's Kanagawa Prefecture west of Tokyo in the early hours of Tuesday morning, 19 people have been left dead and at least 25 others injured, 20 of whom have sustained critical wounds, local police and investigative sources said.

Local police stationed in Sagamihara City where the attack took place have since confirmed the arrest of Satoshi Uematsu, 26, in conjunction with the mass killings, after he turned himself in at around 3:00 am local time, shortly after the savage stabbing rampage took place at the care facility.

Local police quoted the suspected assailant as saying "I did it" upon his arrival at Tsukui Police Station, where a bloodied Uematsu had driven himself after the attack at the residential home that took care of people of all ages with mental disabilities, to hand himself in to police custody.

Uematsu was also quoted by the police as saying, "It's better that the disabled disappear."

Investigative sources believe that the assailant, who, although currently unemployed, claimed he used to work at the Tsukui Yamayuri-en care facility where he systematically bludgeoned dozens of disabled residents, may be harboring deep resentment for those with disabilities, or for the facility itself where he used to work.

Uematsu, who was carrying a bag full of bloodied knives and blades of different sizes when he arrived at the police station after the frenzied attack, has been identified as living not far from the care facility, and is currently undergoing mental health checks, sources close to the matter said Tuesday, as part of the police's investigation.

His actual motive for the deaths of 10 women and 9 men, according to the current death toll from hospital officials, however, is still being investigated, according to local officials.

Hospital staff talking to local media said the death toll will likely rise, however, as many of those injured in the attack sustained serious "life threatening injuries."

Kitasato University Hospital admitted 13 patients who had been stabbed and slashed, with staff there saying that at least eight of them had "suffered serious neck injuries."

Police were first alerted to the mass killing, following a desperate call from a shaken employee just after 2:30 a.m. who said that a man wielding a knife had just broken into the facility.

The employee was quoted as saying to the police that a man had "broken into the facility" and that "something horrible" was happening.

The operator of the care home said Uematsu had broken into the facility by smashing a window with a hammer at the east residential building. Police retrieved a hammer from outside the broken window, they confirmed, adding that Uematsu had almost certainly gained access to the building at this point.

Being that he had knowledge of the layout of the facility, investigators said that Uematsu made his way around the building systematically stabbing the vulnerable residents multiple times as they either slept or lay helpless in their beds.

Police, however, were on the scene within minutes, the facility owner said, by which point the suspect had driven off, meaning his multiple slayings were carried out swiftly from bed to bed and with almost military-like precision.

On turning himself into the police, Uematsu was arrested on suspicion of attempted murder and unlawful entry to a building, local police sources said.

The residential care facility, the name of which translates in English to Tsukui Lily Garden, is run by a social welfare organization and was initially developed by the local government.

The facility, with its 30,000-square-meter area, can house up to 160 residents and according to local sources as many as 149 residents were on site when the attack happened, many of whom are believed to be in their sixties.

The facility is located some 50 km from central Tokyo in a residential area surrounded by houses and an elementary school and housed residents aged between 18 and 70 years of age, with 40 of them believed to be aged over 60.

All of the residents, the health ministry said, are designated as being between levels 4 and 6 in terms of how much care they require. Around 115 of those residing at the facility have been categorized as level 6, the ministry said, the highest care level on the scale.

Tuesday's attack marks the worst mass killing Japan has seen in decades, with the government here condemning the attack as being "highly distressing."

Other deadly mass murders here include the 1995 Aum Shinrikyo cult's sarin gas attack on Tokyo's subway system which killed 13 people and injured thousands more and a 1999 attack which saw a man ram his car into a station in Shimonoseki station and go on a stabbing spree killing a total of 5 and injuring 10.

In 2001, 8 children were killed and 15 injured following a stabbing spree at an elementary school in Ikeda, which rocked the nation, and in 2008 after ploughing his truck into pedestrians in Tokyo's Akihabara district, a knife-wielding man killed a total of 7 people and injured 10 others.

Also in 2008, 16 lives were lost following a deadly arson attack at a video parlor in Osaka.