Tokyo prosecutors have raided the headquarters of two of Japan's largest construction firms as part of an investigation into allegations of anti-trust violations in connection with securing contracts for Japan's multi-billion-dollar, magnetically-levitated, or maglev, train line projects.
Investigators pounced Monday on the offices of Kajima and Shimizu.
A spokesman for Kajima told the French News Agency (AFP) that it would "fully cooperate with the investigation."
Media reports say the probe focuses on four firms. The other two companies are Taisei and Obayashi.
Obayashi was raided earlier this month on suspicion of obstructing other companies' bids on the railway projects.
Taisei has not been raided.
Local media report that the four companies each have a roughly equal number of orders for about 70 percent of the most recent maglev bids.
The giant train project is expected to cost $80 billion. The maglev trains will run at 500 kilometers per hour, about twice as fast as Japan's current bullet trains.
The maglev trains are expected to come into service in 2027, connecting Tokyo, Nagoya and Osaka.