RMS Laconia, carrying 2,732 crew, passengers, soldiers and prisoners of war, was torpedoed and sunk by U-156, a German U-boat, off the West African coast. Operating partly under the dictates of the old prize rules, the U-boat commander, Korvettenkapitän Werner Hartenstein, immediately commenced rescue operations. U-156 broadcast their position on open radio channels to all Allied powers nearby, and were joined by the crews of several other U-boats in the vicinity.

After surfacing and picking up survivors, who were accommodated on the foredeck, U-156 headed on the surface under Red Cross banners to rendezvous with Vichy French ships and transfer the survivors. En route, the U-boat was spotted by a B-24 Liberator bomber of the US Army Air Forces. The aircrew, having reported the U-boat's location, intentions and the presence of survivors, were then ordered to attack the sub. The B-24 killed dozens of Laconia's survivors with bombs and strafing attacks, forcing U-156 to cast their remaining survivors into the sea and crash dive to avoid being destroyed.

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