A German sailor whose mummified body was found on a yacht adrift off the southern Philippines last week died of a heart attack about a week earlier, an autopsy report says.

Police named the victim as Manfred Fritz Bajorat based on documents found on the yacht on Friday, but still do not know where he had sailed from or where he was heading.

WARNING: Contains graphic image

“The cause of death is acute myocardial infarction based on the autopsy by [the] regional crime laboratory,” national police spokesman Chief Superintendent Wilben Mayor told AFP news agency.

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“The German national is estimated to have been dead for more or less seven days,” he added, citing a statement by police.

Local fishermen found the 13-metre yacht with a broken mast adrift on the western edge of the Pacific Ocean, with the mummified corpse of the naked man hunched over a table in the main cabin.

Police launched an inquiry to determine whether he had been the victim of a crime, but the autopsy result indicated otherwise.

“Saltwater in the air could have mummified his body,” Barobo town’s Deputy Police Chief Inspector Mark Navales said.

Police in Barobo town on the east coast of Mindanao island, where the corpse was taken, said the German embassy was arranging for a relative to fly to the Philippines.

The stunning image shows Mr Bajorat next to the radio of his yacht. Photo: Barobo Police Station

“It appears he has a daughter based in Germany and the embassy is to fly her here to identify the dead body,” Chief Inspector Dominador Plaza, the Barobo police chief, told AFP.

The embassy referred queries to the German foreign ministry.

German-language documents, old pictures of a family visiting Paris landmarks, rice and tinned food lay scattered in the cabin of the boat, which had taken in water and was listing, police said.

One document photographed by police indicated the boat had obtained clearance from maritime police in Sao Vicente in 2013, although it was unclear if it was issued in Cape Verde or Brazil, which both have ports of the same name.