The bid-rigging scandal involving the Defense Facilities Administration Agency widened Thursday after investigators said bids for a runway relocation project at the U.S. Marine Corps Iwakuni Air Station in Yamaguchi Prefecture were also rigged.

Contractors were found to have won bids by tendering quotes closely matching the cost estimates of the agency, which manages Self-Defense Forces and local U.S. military facilities, the investigative sources said.

The successful bids in most cases came within at least 95 percent of the cost estimates.