Those arrested include managers and staff members at the company operating the bridge in Gujarat, which had been closed for repairs and reopened just four days earlier.

MORBI, India — Police in western India arrested nine people on Monday as they investigated the collapse of a newly repaired 143-year- old suspension bridge in one of the country’s worst accidents in years, officials said. The collapse Sunday evening in Gujarat state plunged hundreds of people into a river, killing at least 134.

As families mourned the dead, attention turned to why the pedestrian bridge, built during British colonialism in the late 1800s and touted by the state’s tourism website as an “artistic and technological marvel,” collapsed and who might be responsible. The bridge had reopened just four days earlier.

Inspector-General Ashok Yadav said police have formed a special investigative team, and that those arrested include managers of the bridge’s operator, Oreva Group, and its staff.

“We won’t let the guilty get away, we won’t spare anyone,” Yadav said.

Gujarat authorities opened a case against Oreva for suspected culpable homicide, attempted culpable homicide and other violations.

In March, the local Morbi town government awarded a 15-year contract to maintain and manage the bridge to Oreva, a group of companies known mainly for making clocks, mosquito zappers and electric bikes. The same month, Oreva closed the bridge, which spans a wide section of the Machchu river, for repairs.

The bridge has been repaired several times in the past and many of its original parts have been replaced over the years.

It was reopened nearly seven months later, on Oct. 26, the first day of the Gujarati New Year, which coincides with the Hindu festival season, and the attraction drew hundreds of sightseers.

Sandeepsinh Zala, a Morbi official, told the Indian Express newspaper that the company reopened the bridge without first obtaining a “fitness certificate.” That could not be independently verified, but officials said they were investigating.

Authorities said the structure collapsed under the weight of hundreds of people. A security video of the disaster showed it shaking violently and people trying to hold on to its cables and metal fencing before the aluminum walkway gave way and crashed into the river.

The bridge split in the middle with its walkway hanging down, its cables snapped.

Police said at least 134 people were confirmed dead and many others were admitted to hospitals in critical condition. Emergency responders and rescuers worked overnight and throughout Monday to search for survivors. State minister Harsh Sanghvi said most of the victims were teenagers, women and older people.