There have been at least three different theories about how Bogle might have been assassinated by intelligence agencies. The case happened during the height of the cold war and rumours of involvement by spies were rife. All the spy theories have held that Dr Bogle was assassinated for one reason or another, and that Mrs Chandler was killed because she was with him at the time.
While such speculation may sound far-fetched, there exist in espionage some unlikely true stories. Georgi Markov was assassinated with a poisoned umbrella in London in 1978, and the Bogdan Stashinski cyanide-gun murders in Ukraine in the late 1950s were murders showing no apparent symptoms. Given this as a background, the murder of Bogle and Chandler with an undetectable poison is not without possibility.
The first of the concrete theories is quite straightforward. Bogle was due was due to take up a position with the Bell Telephone Company in the USA, The theory is that MI5, not wanting Bogle's knowledge to go to the US, assassinated him.
A second theory, put forward by the former British spy Peter Wright, was that Dr Bogle was both an informant for ASIO and a member of the Communist Party. Wright suggested that Bogle had been assassinated when this duplicity was discovered. Being the height of the Cold War, communists were considered to be the enemy.
The third theory, expounded by Catherine Dalton in her book Without Hardware, was that Bogle offered to help her investigate her husband's death. Clifford Dalton, inventor of the fast breeder nuclear reactor, died in 1961 of a mysterious illness. He was determined that the technology should remain in Britain, and should not go exclusively to America. According to Mrs Dalton, Bogle supported her, and when his enquiries began to get attention, the intelligence community had him killed.
The first of these three theories is the easiest to dismiss. There is obviously no way of having any evidence to disprove the theory, but on the other hand there would surely exist less drastic ways to stop Bogle's departure.
The second theory is, in a way, the most intriguing of all. The fact is, there was a person involved in the case who was both an ASIO informant and a member of the Communist Party. That person, however, was Geoffrey Chandler. If the deaths were an intended assassination then they very clearly got the wrong man. The theory leaves unexplained how Geoffrey Chandler and Gilbert Bogle, two very different men with very different cars, could be mistaken for one another by spies. They were not even dressed the same, and Chandler had a beard.
So what about the FBI's file on Bogle? Marian Wilkinson, a journalist for the National Times, applied under the US Freedom of Information act for access to the file. The FBI, under section 552(b)(i) of the legislation, withheld 18 pages of the file. To quote the relevant part of the legislation, the FBI can withhold information if it is "currently and properly classified...in the interest of the national defense or foreign policy; for example, information involving intelligence sources or methods." According to Wilkinson, the FBI ran a security check on Bogle before his death, at the instigation of Bell Laboratories. Wilkinson also said that according to excellent sources in ASIO, ASIO was conducting an undercover operation affecting Bogle and his colleagues just before his death, but that the details of this operation were (and presumably still are) a secret.
There remains the factor of Bogle's work. Bogle was an expert in solid-state physics and was involved in research on masers, which are related to lasers. One of Bogle's colleagues, Arthur Harper, denied at the inquest that Bogle's work could have any significance to international security. This was quite clearly untrue. The technologies that Bogle was working in have vital military applications, and some of these were known and anticipated at the time. Bogle himself pointed out in a March 1961 paper that masers had been used to control the Nike-Ajax guided missile and to detect weak radar signals. More recently, the use of laser technology in laser-guided bombs and other military applications is well known.
Bearing this in mind, what could there be in Bogle's FBI file which poses such a risk to US national security? It is impossible to know, and this has fueled almost endless speculation. However, there are dissenting voices. Bill Jenkings, crime reporter for the Daily Mirror, said that Commissioner Norman Allan sent the entire police brief to the FBI for analysis. According to Jenkings, J. Edgar Hoover sent back a reply saying that there were no similar cases in America, adding "I hope the weather is good over there, Mr Allan". Jenkings said that this was all there was to the FBI file, and that it remained classified because it was a highly sensitive investigation.
There is an alternative and more plausible explanation. The FBI quite possibly conducted its own investigation into Bogle's death, just as it was rumoured to have investigated Bogle before he died, at the instigation of Bell Laboratories. To release the entire file on Bogle would therefore release any reports on Bogle. More crucially, it would mean revealing the FBI's intelligence sources. It follows that the FBI, not wanting to reveal its sources, has withheld 18 pages of the file.
One of Bogle's former colleagues, Doug Milne, has also made a telling observation. Bogle may have been a very talented scientist, but he was not a genius. He was leaving to Australia to work at Bell Laboratories, but he would have been one of many scientists working there and would not have stood out. To put it simply, he was not important enough to be worth killing.
Other speculation: