It has been a good week for assassins. No sooner is Pierre Gemayel gunned down in the streets of Beirut than Alexander Litvinenko dies mysteriously in London.

The deaths are unrelated save for the accusations that they were state-sponsored. The problem is that no matter how strenuously the Syrian and Russian governments deny complicity, sceptics bring up their past form in the dark art.

In the early 1950s, Moscow was particularly concerned by the National Labour Union (NTS), a West German-based Soviet dissident organisation spreading social democratic ideals behind the Iron Curtain. So agents were sent over to assassinate the NTS leadership.

Nikolai Khokhlov was given the job of executing a “wet affair” (in Soviet spooks’ parlance) on Georgi Sergeivich Okolovich, one of the NTS’s leading lights. His weapon was a cigarette case fitted with an electrically operated miniature gun (compete with silencer) that fired cyanide bullets.

In February 1954, Okolovich got a knock at the door of his Frankfurt apartment. It was Khokhlov. “Georgi Sergeivich,” the uninvited guest introduced himself, “I’ve come to you from Moscow. The Central Committee of the Communist Party of the Soviet Union has ordered your assassination.”

Bad news, it might be thought. However, Khokhlov proceeded to announce that he had decided to disobey the order. He had been reading some of Okolovich’s NTS literature and concluded it made some valid points. More importantly, his resolve to murder in the name of communism had been weakened by the influence of his wife, a clandestine Christian. He promptly handed himself over to the CIA.

While Khokhlov proceeded upon the dangerous paths of lecture tours and a book contract, his former employers decided to enact the old saying that “a traitor is his own murderer”.

Attending a conference in West Germany in September 1957, a cup of coffee was placed in front of him. He took a sip. It tasted fine but, as he put it, “my subconscious reacted”. He had not ordered it and so put it aside. He was soon critically ill; his blood turned to plasma and his hair fell out. He had been poisoned by radioactive thallium. The supposed advantage of thallium was that it disintegrated quickly and would not show up in a post-mortem. Only his decision to stop drinking the coffee saved his life.

The following month, a Soviet agent using a cyanide spray gun designed to induce a heart attack murdered Lev Rebet, another NTS leader. Four years later, Rebet’s remorseful assassin also defected to the West.

Will it take another guilty conscience to disclose what doctors and commentators cannot — who and what killed Mr Litvinenko?

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