An hour later, the German flotilla encountered the Swedish cruiser HSwMS Gotland; the cruiser shadowed the Germans for two hours in the Kattegat.[37] Gotland transmitted a report to naval headquarters, stating: "Two large ships, three destroyers, five escort vessels, and 10–12 aircraft passed Marstrand, course 205°/20'."[35] The OKM was not concerned about the security risk posed by Gotland, though both Lütjens and Lindemann believed operational secrecy had been lost.[37] The report eventually made its way to Captain Henry Denham, the British naval attaché to Sweden, who transmitted the information to the Admiralty.[38] The code-breakers at Bletchley Park confirmed that an Atlantic raid was imminent, as they had decrypted reports that Bismarck and Prinz Eugen had taken on prize crews and requested additional navigational charts from headquarters.