IT is one of the greatest maritime mysteries - a ship's entire crew found dead with their faces frozen in fear after a spooky SOS call.

And a secret CIA memo reveals the agency believed the doomed SS Ourang Medan could hold the key to a series of other mysterious disappearances in one of the world's busiest shipping lanes.

5 The SS Ourang Medan was found with the entire crew dead and their faces frozen in fear in one of the world's greatest maritime mysteries

5 A memo by C.H Marck Jr, assistant to the Director of the CIA Allen Dulles, in 1959

The dutch vessel is said to have sent a distress call in 1948 while sailing the Strait of Malacca - the same area where Malaysia Airlines flight MH370 disappeared in 2014.

The crew of a nearby ship, the Silver Star, heard a Morse code SOS from a signaller on board SS Ourang Medan.

It said: "All officers including the captain are dead, lying in chartroom and bridge. Possibly whole crew dead … I die."

When sailors found the doomed ship they were reportedly greeted with a nightmare vision.

The entire ship was littered with corpses, all with bulging eyes and terrified expressions on their faces.

Their mouths were wide open as if in the middle of screaming and their arms were outstretched as if reaching for something.

But to make the finding even more bizarre, the crew appeared to show no signs of any injuries that could have caused their deaths.

FROZEN IN FEAR

The rescuers planned to tow the ship to port but a fire broke out, followed by an explosion and it sank without trace.

The final twist in this fishy ghost story is that to this day nobody has found any trace of the ill-fated vessel.

Some question if the SS Ourang Medan existed at all as there is no mention in the Lloyds List of shipping, and there were no records on the Silver Star detailing the attempted rescue.

The coast guard didn't report it until may 1954, six years after the vessel sank.

Conspiracy theorists believe several countries worked together to cover it up.

Some suggest noxious gas bubbled up from fissures in the seabed and engulfed the boat, while others blamed the supernatural.

And an eyebrow-raising top secret CIA document, which wasn’t released to the public until 2013, pondered whether it may have involved “something from the unknown”.

It was penned by C.H. Marck Jr, assistant to the Director of the CIA Allen Dulles, in 1959 and addressed to an unknown recipient.

“I feel sure that the SS Ourang Medan holds the answer to many of these aeroplane accidents and unsolved mysteries of the sea,” he wrote.

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Marck then made reference to “fiery spheres” of destruction before concluding: “The enchanting sea, what terrifying ‘secret’ does it hold? I feel sure that the SS Ourang Medan also holds the answer to this ‘secret’.”

The narrow waterway in southeast Asia that connects the Pacific and Indian oceans is also steeped in history, its seabeds the final resting place of many shipwrecks.

5 The dutch vessel is said to have sent a distress call in 1948 when sailing in the Strait of Malacca

5 A search boat explores the Strait of Malacca looking for the missing Malaysia Airlines flight Credit: Handout

5 The aeroplane vanished in 2014 and remained an unsolved mystery