French and Cambodian investigators yesterday questioned relatives of a Frenchman who, along with his four children, died last year in mysterious circumstances, a provincial official said.

According to Kampong Speu provincial court investigating judge Chhim Rithy, the father-in-law, mother-in-law and sister-in-law of Laurent Vallier, along with an unknown fourth witness, were brought to the French Embassy yesterday to be questioned by French investigating judges, one day after the trio was questioned by provincial police. Earlier this year, the three were questioned at the provincial court after applying for the titles to two pieces of land belonging to Vallier and their daughter, who died in 2010 during childbirth.

In January 2012, the bodies of Vallier and his four young children were found submerged in a pond behind the family’s home – some four months after they were last seen. A preliminary report by Cambodian authorities ruled it to be a murder-suicide, though the case remained under investigation by the French.  A team of French investigators arrived in Cambodia on Sunday and began their work in Kampong Speu on Tuesday.

Rithy said that more than 20 witnesses including village and commune chiefs, neighbours, and the children’s’ teachers would be questioned over the course of the next two weeks.

“To date, we have completed more than 50 per cent [of the list]. We conducted investigations of the people living in that area, but the French side wants to go through the investigation again,” he said. “The [French] technicians are investigating his home, while investigating judges are working at the embassy,” said Rithy.

Questions to the French Embassy went unanswered.

Kim Bunheang, a former neighbour of Vallier’s, said he and two others had been asked to appear at the provincial police headquarters on Friday for questioning.

“I will say what I remember and what I have said before. I will tell French judges how after the death of his wife, he also asked for my daughter’s hand in marriage, but due to legal problems, he could not marry her,” he said.