In September 2014, a couple, as well as a woman and her daughter, died when the Bitoulet River, a tributary of the Orb, flooded the campsite in the spa town of Lamalou-les-Bains.
The municipal site, three metres (ten feet) above the river, had been established in 1982. In 1989, the area on which it was built was declared a flood-risk zone on account of the severe storms that often caused rivers in the region to overflow.
A criminal probe was opened after the tragedy, which lead the spa town's mayor, Philippe Tailland, to be placed under judicial investigation – the equivalent under French law of being charged.
Since Tuesday, six other local officials have been formally questioned in connection with the incident and three others, including Tailland's predecessor, were referred to an investigating magistrate.
The investigation focussed on the exact cause of the disaster – probably the rupturing of a natural dam made of vegetation – and on why the campsite remained open after the designation of the flood zone.
Tailland had only been in his post for a few months at the time of the accident.