Knife attack leaves many wondering if police did enough

TOKYO — Hours before 19 people were stabbed to death at a residence for people with disabilities in Japan early Tuesday, police officers drove up to the home of the man who would be accused of the grisly crime.

The house was empty, according to a neighbor, and the patrol car left.

The next time authorities knew the whereabouts of the man, Satoshi Uematsu, police said he confessed to the worst mass killing in Japan in generations.

Uematsu, a 26-year-old former employee of the residence where the murders took place, was known for months to law enforcement and mental health authorities. They foresaw trouble but proved powerless to stop it, and now many Japanese are asking why.

Uematsu appears to have slipped through cracks in the systems that are supposed to identify and treat mentally ill people and keep those with the potential for violence from harming others.