The body was found by a Spanish fisherman the morning of April 30, 1943. Spanish naval authorities took custody of the remains and the briefcase. A British Vice-Consul in Huelva named Francis Haselden learned of the discovery and reported it to the Admiralty while taking steps to appear only naturally interested in the fate of a British officer.
The autopsy was conducted on May 1, 1943. Haselden had positioned himself to help manage how it proceeded. The autopsy concluded with a finding of death by asphyxiation through immersion in the sea. The cause of Martin’s actual death, phosphorus poisoning in a London hospital weeks earlier, was not detected.
Glyndwr Michael was buried with full military honors in the Nuestra Señora cemetery in Huelva on May 2, 1943.
The briefcase’s contents then began moving through the intelligence chain.
German Abwehr operative Adolf Clauss had learned of the body’s discovery through his own sources. He was working alongside a more senior German agent named Karl-Erich Kühlenthal, the head of the Abwehr network on the Iberian Peninsula, to obtain access to the documents.
The technical challenge was that the envelopes were sealed with official wax. Breaking the seals would immediately signal that the correspondence had been tampered with. Spanish officials aligned with German intelligence found a solution that required considerable dexterity: they extracted the damp letters from their envelopes by winding them around a thin probe and drawing them out through the unsealed flap without breaking the wax closure. The letters were photographed, dried, soaked in salt water for twenty-four hours to simulate their extended immersion time, and then carefully reinserted.