JOIN USXavier Dupont de Ligonnes, 50, had begun telling his friends in Nantes that he was a secret agent and his family had gone to Australia as part of the witness protection programme,
The Sun reported.
He, however, fled after neighbours alerted the police after not getting any news about the family for three weeks. Police reached the family's empty home and made the grim discovery of a severed leg under the garden terrace.
A thorough search revealed the freshly dug grave containing the bodies of Ligonnes's wife Agnes, 49, and the four children - Tomas, 21, Arthur, 18, Anne, 16, and Benoit, 13. The family's two labradors were also among the dead.
"Friends said the father (Ligonnes) claimed to be a secret agent who was leaving as part of a witness protection programme," prosecutor Xavier Ronsin was quoted as saying.
A neighbour said: "They were regular churchgoers - very quiet and devout." A lead was received from 400 miles away in the Var region of the South of France after Ligonnes used a credit card in Roquebrune-sur-Argens. His Citroen C5 car was found there.