Four people who work for the operator of the South Korean ferry that sank last month, killing 263 people and leaving 39 others missing, have been arrested for allegedly overloading the Sewol with cargo, a senior prosecutor told the New York Times on Tuesday.

The employees of the Chonghaejin Marine Company face accidental homicide charges for overloading the Sewol, which investigators believe was one of the causes for the South Korean ferry sinking. Prosecutors contend the workers either ignored the consequences of putting excessive cargo on the Sewol or ordered the ship to be overloaded, the Times reported.

The Sewol sank in the sea off Jindo on April 16 after it listed on its side. The incident drew anger from around the world after it was revealed that crew members saved by the South Korean Coast Guard allegedly didn’t make attempts to rescue passengers. Those crew members, along with the Sewol’s captain, Lee Joon-seok, are facing charges. Crew members also face negligence of duty charges and abandoning passengers on board.

The South Korean ferry disaster led the country’s prime minister, Chung Hong-won, to resign from office late last month. The search effort for the remaining missing passengers is ongoing. A diver for Undine Marine Industries, who conducted a search Tuesday morning, died Tuesday morning shortly after a dive.