55-year-old mystery case! Australian Prime Minister missing from swimming, assassinated by frogmen? Or was he buried in the mouth of a shark?

In January 1966, Liberal Party leader Harold Holt became Prime Minister of Australia. A career politician, he entered parliament at the age of 27 and became a government minister at 30.

Two incidents occurred in Australia in mid-1966, one in which the window of his prime minister's office was shot out by a sniper, followed by the assassination of opposition leader Arthur Calwell. Calwell was assassinated. Holt, who was supposed to go without bodyguards, eventually accepted them, but he refused to have any protection from them while on vacation, arguing that it violated his privacy. And his wife, Zara, later implied that he did so to hide his extramarital affairs.

Holt was passionate about the outdoors and had beach houses in several locations. He enjoyed swimming, snorkeling and fishing, and was able to hold his breath underwater for long periods of time.

On May 20, 1967, while diving at Cheviot Beach on the Mornington Peninsula, Holt had a dangerous encounter and was later pulled ashore by his diving companion, who turned purple and spit up large amounts of seawater. He said: "This is the closest I've ever come to drowning in my life!"

A few months later, on August 5, he was spearfishing on Dunker Island in the Great Barrier Reef, and had a close encounter with danger.

But that didn't change the Australian prime minister's love of the sea, a passion that eventually got him killed!

Around 10 a.m. on December 17, 1967, he drove to the local grocery store, where he bought insect repellent, peanuts and the weekend newspaper.

One of the headlines in The Australian that day was "PM advised to swim less".

At 11:15 a.m., he and four others set off for Cape Newport, where they hoped to see solo circumnavigator Alec Rose cross the rift into Port Phillip Bay.

Ending the event on the way back to Potsie, Holt suggested the group stop at Cheviot Beach for a swim - it was already 12:15 p.m. - and he wanted a swim to whet his appetite before lunch.

Holt was familiar with the area and had swum there many times before.

Without hesitation, Holt jumped into the water, despite the huge waves and visible eddies. Only one person followed the prime minister into the water as the others thought it was unsafe to do so.

However, Holt got rid of his entourage, swam to deeper waters and quickly submerged and disappeared from sight. And everyone waited for a long time, but did not wait until the Prime Minister reappeared!

The entourage panicked, and the one of them who went underwater immediately drove to the nearby Portage West Officers' School, an Australian Army training base, but the military students were on annual leave at that time and the school was almost deserted. The police had to be contacted and "the largest search operation in Australian history" was launched.

The search for Holt began at 1:30 p.m., when three local amateur divers entered the water and found rough seas. They were soon joined by helicopters, boats, police divers and two Navy dive teams. However, due to the harsh conditions and limited equipment, very little progress was made.

By the end of the day, more than 190 personnel were involved in the operation and eventually 340 people joined the search in the following days.

The search was officially called off by January 5, 1968, due to poor weather and sea conditions, by which time there was still no sign of the Prime Minister and his body had not been found.

Many theories exist about the death of Harold Holt.

The first was, of course, drowning.

Tom Frame, Harold Holt's biographer, says:- "In fact, no one would suspect that Harold Holt drowned-he was just one of the ordinary Australians who drowned every year through errors of judgment or bad luck."

Holt likely misjudged his swimming ability and the harshness of the conditions and ended up exhausted. Either he had a heart attack, or was struck by driftwood, or was stung by a jellyfish, or was attacked by a shark.

Holt's body may have been trapped underwater or washed out to sea at low tide.

The results of the police report were released on January 5, 1968, but the lack of evidence did not lead to any definitive conclusions.

Senior pathologist James McNamara claimed that Holt's body may have become entangled in seaweed and then been eaten by marine life (specifically sharks, crayfish and/or sea lice). If so, "the body would have become a skeleton within 24 to 48 hours."

Some of those involved in the investigation later reported that certain relevant information was deliberately removed from the final report, for example, it was said that Holt's bag contained several cans of beer.

In addition to claims like the swimming accident, some believe that Holt's death was not an accident but that he chose to end his life.

Proponents of the suicide theory claim that Holt was depressed and mentally unstable and committed suicide because he believed his political career was in danger. However, a 1968 police report clearly ruled out the possibility of suicide.

Beyond that, the favored conspiracy theories were soon rampant!

A report in the Australian Sunday Observer in 1968 claimed that Holt was assassinated by the U.S. Central Intelligence Agency, allegedly because he wanted Australian troops to withdraw from Vietnam.

There was also speculation in the media that Holt was killed by the North Vietnamese, even going so far as to describe in graphic detail that he was killed after being incapacitated by a nerve agent.

There was also speculation that he may have faked his own death, giving up everything to be with his lover.

In 1983, British journalist Anthony Gray published a book, "The Prime Minister is a Spy," in which he claimed that Holt had spent his life spying for an Eastern country.

According to Gray's account, Holt eventually faked his own death and was then rescued by the country's frogmen in the water and taken to a waiting submarine.

Critics, however, argue that Gray was full of crap, not to mention that the country had not yet built a nuclear submarine capable of traveling long distances, and that even a submarine could not be found so close to the coast. Holt's wife also specifically explained that his husband did not like Oriental food.

Holt's death has also had a major impact on Australian political circles, bringing an end to the so-called "Age of Innocence" in Australia, as it means that the country's leaders can no longer keep their private lives completely away from the scrutiny of their bodyguards and the arrangements of the security services.

On the first anniversary of Holt's death, a memorial plaque was fixed to a reef about 15 meters below the surface of Cheviot Beach.

There are memorials to Holt on the cliffs of the beach and at the General Melbourne Cemetery, the latter with the inscription "He loved the sea".

Was Holt missing or dead? This question remains a mystery until today.