The charred corpses of two men, both with knife wounds, were found Monday morning after a fire broke out in a building in Minato Ward, Tokyo, leading police to investigate the case as a possible murder-arson.

The fire broke out at around 7:40 a.m. in the fourth-floor accounting office of financial and commodities futures dealer Ace International Inc., the Tokyo Fire Department said.

The bodies were later identified as those of Yasufumi Yamamoto, 41, the firm's managing director; and Teruo Kondo, 49, chief of the management department, according to the Metropolitan Police Department.

The corpse of Kondo was found lying face down on the office floor. He had a stab wound in the back and a kitchen knife with a 20-cm blade was found nearby, police said. A melted PET bottle was also found near the body, they added.

Yamamoto's corpse had stab wounds to the abdomen. Police are trying to determine the cause of death.

An oil-like substance was apparently sprayed over the bodies, they said.

The office safe was apparently left untouched and there were no signs of a burglary, police said.

According to office employees, Yamamoto, from Funabashi, Chiba Prefecture, and Kondo, from Yokohama, were working at the office since early Sunday morning to deal with accounting-related problems ahead of an internal inspection at the firm scheduled for Monday.

The two reportedly spoke via phone with an accounting section chief at around 7 p.m. Sunday, and at around 9 p.m. with another employee of the accounting section.

Ace International was established in 1981 and employs about 300 people. It has branch offices in Osaka, Nagoya and Sendai.

Court records show Ace International has been the target of more than 40 damages suits since 1997.

The 11-story Shin Toranomon Building where the fire occurred stands along the busy Roppongi avenue near the Tameike crossing in the Akasaka district. The company maintains offices on the first, third and fourth floors of the building.

As it engages in international trading in financial and commodities futures, the office is staffed on a 24-hour basis during weekdays. However, only Yamamoto and Kondo were working Sunday.

According to officials of other companies that have offices in the building, all of the offices there are closed on Sundays, and an ID number is required to enter the building and another is necessary to access the fourth-floor offices.