A new explosive book titled ‘Drugs as Weapons Against Us’ suggests the ex-Beatle was killed by US intelligence agencies to prevent him influencing people to halt Lennon’s support of “radical leftist” ideologies. Author John Potash also claims the CIA tracked various high-profile pop stars, including rapper Tupac Shakur and Nirvana frontman Kurt Cobain, before their untimely deaths, amid fears over similar influences. Liverpool-born Lennon was gunned down aged 40 by Mark David Chapman outside his New York home in December 1980. Chapman, then 25, was described as a crazed fan, and sentenced to 20 years to life in jail after pleading guilty to second—degree murder.

GETTY The book claims that the CIA monitored and even arranged the death of Lennon - something it denies.

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There have been a number of conspiracy theories surrounding his death ever since. The book recounts an investigation by former Sunday Express legal correspondent Fenton Bresler, who obtained classified documents from the FBI and CIA. The documents were said to show the star’s arrest for drugs use in 1972 was “to neutralise and disrupt” his activities. They suggested Lennon was tracked by the intelligence agencies during the 1970s.

This exemplified the international interest and influence of Lennon, underscoring why his leftist activism was a threat to the CIA and the oligarchy. John Potash

According to the book, Lennon's activities included him holding anti-war events and even a benefit concert to free imprisoned activist John Sinclair. Potash says the US intelligence agencies were becoming more concerned with Lennon after he moved away from drug use and towards activism – and he was just one month away from becoming an American citizen at the time of his death. Mr Potash wrote: “This exemplified the international interest and influence of Lennon, underscoring why his leftist activism was a threat to the CIA and the oligarchy.” The book's most staggering suggestion is that Chapman may have been trained to kill in Beirut, where the CIA had a heavy presence in the 1970s. An earlier book by Phil Strongman, John Lennon: Life, Times and Assassination, explored the idea Chapman was "programmed" to carry out the killing.

Unseen pictures of legendary John Lennon Tue, March 15, 2016 Musician and former Beatle John Lennon, who was assassinated on 8 December 1980. Here is his life in pictures. Play slideshow OmegaAuctions/BNPS 1 of 52 John Lennon queues for food on the set of How I Won the War