In April 2011, police dug up the back garden of the Dupont de Ligonnès family and made a shocking discovery. Agnès Dupont de Ligonnès and her four children had been shot and their bodies buried under the back patio of their own home, and their father, Xavier Dupont de Ligonnès, had disappeared.
Sources:
https://en.wikipedia.org/wiki/Dupont_de_Ligonn%C3%A8s_murders_and_disappearance
https://www.radiotimes.com/tv/documentaries/true-crime/xavier-dupont-de-ligonnes-unsolved-mysteries/
https://unsolvedmysteries.fandom.com/wiki/Xavier_Dupont_de_Ligonn%C3%A8s
https://www.strangeoutdoors.com/strange-indoors/xavier-dupont-de-ligonnes
https://www.grunge.com/224521/the-untold-truth-of-the-dupont-de-ligonnes-murders/