The main investigation concerned a company that was suspected of illegally manipulating currency markets.

The investigations have concerned a wide spectrum of charities.

The most detailed investigations have concerned the Sellafield nuclear reprocessing plant in West Cumbria.

The second investigation concerns the local and foreign businesses and individuals alleged to have financed the coup.

His most detailed investigation concerned the women's camp at Ravensbruck.

The investigation concerns the possibility that, had it not been stopped, it might have occurred.

Yet another investigation by the Ministry of Health concerned the importation and handling of cadavers by the school.

This in-depth investigation concerned the battle between civil rights forces and the police of Birmingham, Alabama.

Their first investigation concerned the derailment of a train caused by the fall of a large casting from a wagon on a passenger train.

The investigation concerned a research firm called Gradient Analytics, which was subsequently dropped.