Police in Japan investigating the collapse of a road tunnel ceiling which killed nine people have searched the offices of the tunnel operator to see if there is any evidence that the company neglected safety.
Hundreds of concrete slabs collapsed deep inside the Sasago Tunnel west of Tokyo on Sunday, falling on three moving vehicles. The accident sparked calls for more spending on Japan's ageing infrastructure.
The tunnel, a major link between Tokyo and central Japan, opened in 1977 at about the peak of the country's post-war road construction boom.
Central Nippon Expressway, its government-owned operator, said it had no record of any repairs performed since then, but company official Satoshi Noguchi said an inspection of the tunnel's roof in September found nothing amiss.
Earlier, authorities raided several of the company's offices, including its headquarters in the central city of Nagoya. About a dozen uniformed police were shown on television entering the headquarters, carrying cardboard and plastic boxes.
"Yes, they are searching our offices here. We will be fully co-operating with them," said Osamu Funahashi, another company official.
The transport ministry, meanwhile, has ordered inspections of 49 other highway and road tunnels of similar construction around the mountainous country.
An estimated 270 concrete slabs suspended from the arched roof of the tunnel, each weighing 1.4 tonnes, fell over a stretch of about 120 yards, Mr Noguchi said. Two other people were injured in the collapse. The operator is exploring the possibility that bolts holding a metal piece suspending the panels above the road had weakened with age, he said.
On Monday, crews had to stop recovery work in the tunnel about 50 miles west of Tokyo because the roof needed to be reinforced to prevent more collapses, said Jun Goto, an official at the Fire and Disaster Management Agency. They have resumed removing the concrete slabs from the tunnel, said Mr Goto, who added that authorities do not expect to find any more victims inside.