Personnel from the Fire Services Department a
Personnel from the Fire Services Department aReuters

Authorities in Hong Kong have arrested seven people and have started a criminal investigation after at least 38 people were killed in the city’s worst maritime disaster in over forty years.

A boat carrying more than 120 employees and family members of Hongkong Electric Co. partially sank on Monday after it collided with a commuter ferry. The boat was heading to Victoria Harbor from Lamma Island, southwest of Hong Kong Island, for a fireworks celebration in honor of China’s National Day.

Rescue divers are continuing their search at the crash site and along the coastline, as it remains unclear how many people remain missing. The government is also investigating why the vessel, named “Lamma IV,” sank so rapidly.

“Looking at the damage, and that Lamma IV sank so quickly, the impact was very powerful,” said Prakash Metaparti, an assistant professor of logistics and maritime studies at Hong Kong Polytechnic University, according to Buisnessweek. “It looks like either one of them or both of them are going at a good speed and that’s why the impact is so severe.”

The crew members, including the captains of both vessels, who were arrested have been released on bail.

“From the investigation so far, we’ve come to the suspicion that the crew responsible for manning the two vessels had not exercised the care required of them by law,” Tsang Wai- hung, the police commissioner, said at a press conference yesterday. “Our investigation will focus on criminal liability as well as assist the coroner’s court if an inquest is held.”

The death toll is the highest in a single marine accident since at least 1984, according to statistics on the website of Hong Kong’s Marine Department.