A home movie purporting to show Marilyn Monroe smoking a marijuana joint has surfaced some five decades after being shot at a gathering with friends in New Jersey.

Collector Keya Morgan uncovered the color footage while researching an documentary which he says will prove Monroe was murdered in August 1962.

The reel-to-reel film, which has no sound, shows Monroe relaxing with female friends in a house and smoking.

Morgan said he bought the footage for 275,000 dollars from one of the women present at the meeting in the late 1950s.

Both that woman and a former FBI agent who knew of the footage told him that marijuana, not tobacco was being smoked.

"The reason we know for a fact it's marijuana is the lady who shot it, she's still alive," Morgan told AFP. "She rolled up the joint and handed it over to Marilyn."

The film shows the Hollywood superstar looking happy and playful.

Morgan said his documentary, "Marilyn Monroe: Murder on Fifth Helena Drive," will show that the FBI believed the actress posed a security risk because she was seeing president John F. Kennedy and dabbling in drugs.

"They felt that Marilyn Monroe posed a security threat to the presidency because she was under the influence of marijuana and under the influence of alcohol, and could be a danger not only to herself but also to the presidency," he said.

For that reason, the FBI at the time sought a copy of the footage from New Jersey, he said.

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