Authorities walk near debris of a bridge that collapsed during construction in Anseong, Gyeonggi Province, Feb. 26. Yonhap

Police on Friday raided the offices of Hyundai Engineering and other companies over a fatal expressway construction site accident in Anseong earlier this week, officials said.

The raid came three days after a bridge collapsed at the construction site in Anseong, some 65 kilometers south of Seoul, killing four workers and seriously injuring six others.

The Gyeonggi Nambu Provincial Police sent investigators to search seven locations, including the headquarters and on-site offices of Hyundai Engineering in charge of construction, the Korea Expressway Corporation that placed the construction order and two subcontractors.

Labor ministry officials also took part in the raid.

Investigators plan to seize documents, cellphones and other items related to construction planning and procedures.

Separately, police and the National Forensic Service plan to conduct an on-site inspection later in the day. (Yonhap)