Roderick Newall, 28, a former lieutenant in the Royal Green Jackets, is scheduled to appear before magistrates in St Helier, Jersey, to face charges of murdering Nicholas and Elizabeth Newall in 1987.
He was brought back to Jersey on Saturday following a 15-month legal battle against extradition.
Soon after his arrival, police examined a wooded area at Greve de Lecq on the north-west coast of the island, 400 yards from the family's former home, and spent yesterday digging there for the bodies of the couple.
The team of 14, including officers from Devon and Cornwall Police, erected plastic tents among oak trees on the hillside before they began excavations. They are using a metal detector to help in their search, which will resume this morning.
Police said they were being hampered in the search by landscaping work that had occurred in the last few years and tree losses caused by the great storm of 1987.
Assistant chief officer Barry Simpson said: 'We are not necessarily hopeful of an early breakthrough. It may take some time. A number of sites are being examined.' Also at the site was a Home Office pathologist, Dr Gyan Fernando, who is attached to the Devon and Cornwall force.
Mr Newall, 56, a Lloyd's underwriter, and his 46-year-old wife were last seen on 10 October 1987 having dinner with their sons Roderick and Mark, in a restaurant near their home in Clos de l'Atlantique, St Brelade, on the island's south- western tip.
Both sons have now been charged with the murder of their parents.
Roderick Newall was charged on Saturday after being extradited from Gibraltar where he was taken following his arrest at sea off the coast of Morocco in August last year.
Mark, 27, a Paris-based financier, was extradited from France to Jersey in April this year. He is being held on remand at the island's prison and is due to make his next appearance before magistrates tomorrow.Reuse content