The former temporary worker at Mazda Motor Corp. arrested last week for killing one of the company's employees and injuring 11 others by hitting them with a car at the firm's Hiroshima plant complex, boasted of outdoing the 2008 massacre in Tokyo's Akihabara district, a friend said.

The friend said Toshiaki Hikiji, 42, of the city of Hiroshima, called immediately before he was taken into custody after the June 22 attack.

The friend said Hikiji told him he had just settled old scores against Mazda and that his attack had surpassed the Akihabara incident, in which a former temp autoworker drove a rented truck into a crowd, then got out and started stabbing people at random. Seven people died in the incident and 10 were injured.