Police say a brawl between a passenger and a bus driver was the cause of the bus plunging off a bridge in south-west China.
A video retrieved from the black box of the bus shows a passenger scuffling with the driver moments before the crash.
The driver then suddenly yanks the wheel hard to the left and the bus veers onto incoming traffic, striking a vehicle before breaking through the rails of the bridge crossing the Yangtze River, in the southwest city of Chongqing.
An eight-second surveillance video released by Chongqing city police on its Weibo social media account shows the two arguing and grappling with each other Sunday morning.
According to investigations, the 48-year-old female passenger had missed her stop and asked the driver to stop in the road.
More than 70 rescue boats came to the scene, including three floating cranes with a total capacity of 125 tonnes.
All those onboard are presumed dead.
The 42-year-old driver, surnamed Ran, told her to get off at an earlier stop.
The driver turned his head to face her several times in the argument.
She first struck him with her hands before launching her cell phone at his head, at which he point he lost control of the vehicle and swerved hard to the left before swinging back in the other direction. Two passengers remain missing, state-run Xinhua news agency reported on Friday. The driver took his right arm off the steering wheel and fought back.
The bus was also salvaged and pulled out of the river.
The bus suddenly veered into the wrong lane and collided with an oncoming auto on Sunday in Chongqing before it drove off the bridge.