Masao Enari KYODO PHOTO

A Tokyo man fatally stabbed his parents and wife, and wounded his sons before injuring himself in an attempted suicide around midnight March 27.

"I did it," bookbinder Masao Enari, 42, told police, leading them to allege he killed his parents and his wife.

His two sons, aged 8 and 4, were wounded, police said.

The police plan to interrogate the bookbinder when he recovers. Enari was concerned about declining business.