Police said Tuesday that they have raided SK Engineering & Construction Co. and its construction site on a U.S. base in central South Korea over slush fund allegations involving a U.S. military official.

The National Police Agency confiscated materials including account books and computer hard disks from the head office of SK E&C in Seoul and its work site at the U.S. Forces Korea base in Pyeongtaek, Gyeonggi Province, a police official said on condition of anonymity.

An SK E&C subcontractor allegedly stashed away about 1 billion won ($890,000) and handed it over to a then USFK official in 2010, according to the official. The now-defunct subcontractor is headed by a former South Korean field officer.

The police have already obtained witness accounts from former employees of the subcontractor. They are currently investigating whether SK E&C was involved.

They have also sent investigators to the U.S. to ask U.S. law enforcement authorities for cooperation in searching for the former USFK official.

In 2008, SK E&C signed a deal with the U.S. Army Corps of Engineers to build the Pyeongtaek base and infrastructure around it for 460 billion won. The base is scheduled for completion by 2016.

The construction of the base was part of a deal between Seoul and Washington in 2004, when the two allies agreed to relocate the U.S. military headquarters in central Seoul and its infantry division near the border with North Korea to Camp Humphreys in Pyeongtaek, some 70 kilometers south of the capital. (Yonhap)