The husband of Magali Blandin, wanted since February 12, was placed in police custody on Thursday, suspected by the Rennes prosecutor of having fomented a criminal project against his wife.
Three suspects were also indicted for "attempted organized gang extortion" and another for "organized gang murder".
Magali Blandin has not given any sign of life since February 11.
Her husband was taken into police custody Thursday afternoon, suspected by the Rennes prosecutor of having fomented against his wife a "criminal project" which dates back to last fall.
The couple had just separated.
The 42-year-old specialist teacher had left the family home and filed a complaint for domestic violence, which was dismissed at the time.
But tensions remained very high, especially over the question of custody of their four children.
The husband had been heard for the first time just after the disappearance of Magalie Blandin, without any material element allowing him to be implicated.
The husband claims to be the victim of an extortion attempt
The investigation rebounded last Sunday with the arrest of four men and a woman, born between 1975 and 2003, suspected of attempted extortion in an organized gang.
Magali Blandin's husband had indeed presented himself at the end of February to the judge in charge of the investigation to inform him that he was the victim of an "attempted extortion of a sum of 15,000 euros" and that he "felt threatened".
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Friday morning, three suspects were indicted for "attempted organized gang extortion" and one of them for "organized gang murder".
In addition, a man born in 1980 in Georgia, neighbor of the husband of Magali Blandin, arrested Tuesday near Cherbourg, is still in police custody.
According to information from Europe 1, Magali Blandin's husband does not deny the organization of a criminal plan fomented in the fall but says he has abandoned it.
He now denies his involvement in the disappearance of his wife.