Six people have appeared before anti-terrorism judges in France accused of providing assistance to a group plotting to execute a chemical attack.
French terrorists were 'making ricin' detainees told authorities
They include two Muslim imams - Chellali Benchellali and Mourad Merabet - who were arrested last week and placed under formal investigation by magistrates.
Their arrests came as part of a long-running French intelligence operation.
It has been looking for links between French Islamic and Chechen militants.
The other suspects are Chellali Benchellali's wife Hafsa, his son Hafid, Abdelwahed Regad, and Abdelwahab Djouba.
Another of the Benchellali's sons, Mourad, is one of six
French detainees being held at the US Navy base at
Guantanamo Bay in Cuba, on suspicion of ties to al-Qaeda.
Chellali Benchellali, an imam in the Lyon suburb of Venissieux and his son Hafed were placed under judicial investigation for "belonging to a criminal association in relation to a terrorist enterprise" and ordered to be held in prison.
Police raids at the suspects' homes in the Paris suburbs of Romainville and La Courneuve revealed diagrams of chemical formulas for explosives and a substance that could make toxic gas, judicial officials said at the time.
On Sunday, French Interior Ministry officials said suspects detained by the police had said Menad Benchellali had hoped to concoct a botulism toxin and ricin.
Police said other detainees had admitted to providing Menad
Benchellali with logistical support, including false identity papers and funding.
Investigators in France are looking for possible links between the Benchellali family and the discovery of ricin in a northeast London apartment in January 2003.
So far 14 people had previously been placed under judicial
investigation in connection with France's "Chechen network" probe.