The barracks at the Cologne-Wahn airbase were sealed off on Wednesday as investigators look into a suspected criminal offence involving irregularities in the water system, dpa was told. The news magazine Der Spiegel first reported on the incident. Following indications of a disturbance, a hole was discovered in a fence, it was reported. This raised suspicion that the water supply could have been sabotaged, although this yet to be confirmed. Water samples were also taken for the investigation. It was no longer permitted to enter or leave the barracks and police have cordoned off a large area, d…