CHEONAN, South Korea-- Two officials of an election campaign bus manufacturer were booked on charges of manslaughter by negligence Friday, three days after two campaign workers for minor opposition presidential candidate Ahn Cheol-soo were found dead in a campaign bus in an accident, police said.

On Tuesday, a local campaign chief and a bus driver for Ahn of the centrist People's Party were found dead inside a campaign vehicle parked on a road in Cheonan, about 90 kilometers south of Seoul, apparently due to gas poisoning from a generator powering an LED screen.

The Chungnam Police Agency said it booked the owner of the company that manufactured the vehicle and an unidentified company official in connection to the accident and is conducting further investigation into the case.

Ahn suspended his campaign and attended the deceased workers' funerals after the accident took place, but he will resume campaigning this weekend, according to his officials.

Source: Yonhap News Agency