Gilbert Collard, a prominent Marseilles lawyer, represents the grandchildren of Gaston Dominici, who was convicted and imprisoned for the murder. Mr Collard said this week that he was preparing documents to justify a re-trial and would submit them by 12 December.
Mr Collard said that, looking into the original investigation, he had found that 'all the hypotheses leading away from Dominici were ignored. I'm not saying Dominici was definitely innocent, just that all the leads were not followed.'
Drummond, 61, and his 48-year-old wife were found shot dead near their car on 5 August 1952 near Digne in the southern Alps. Their 11-year-old daughter was found still just alive. Her skull had been crushed.
The corpses were found by Gustave Dominici, the son of Gaston. Gustave, who is still alive, was sentenced to a two-month prison term for non-assistance to persons in danger because he did not call an ambulance in time to save the girl.
The Dominici family, whose farm the Drummonds had visited the previous day, were immediately among the prime suspects.
Gustave Dominici, who was released from prison in 1960, confessed to the crime in November 1953 only to retract later.
On 28 November 1954, Gaston Dominici was sentenced to death but this was commuted to life imprisonment. He died in 1964.