Societe Generale probe - Martial Rouyere Now Questioned
The bank says he acted alone, but Kerviel said during questioning that his superiors looked the other way when he was making money for the bank.
In the lawyer's letter, Canoy asked the judges to question Martial Rouyere, the head of the trading desk where Kerviel worked. Canoy, who has access to legal documents filed in the case, suggested Rouyere had knowledge of Kerviel's activity but did not stop it because in 2007 Kerviel's trades were gaining money for the bank.
Officials at Societe Generale would not comment on Canoy's claim, or say whether Martial Rouyere is still employed with the company.
Martial Rouyere's name repeatedly came up in computer text messages Kerviel sent to a broker who has been questioned in the case, according to excerpts of the messages published in Nouvel Obs weekly over the weekend.
Kerviel was questioned for a third time Wednesday, for five hours.
In his statement to the police in late January, Kerviel identified two supervisors of his equity derivatives trading team - known as Delta One - whom he said were familiar with his activities going back to last April.
These colleagues, according to lawyers with knowledge of the case, were Martial Rouyère, head of the Delta One trading desk, and his deputy, Eric Cordelle.
Rouyère has since been questioned by the French authorities, and a lawyer for Société Générale, Jean Veil, has said that he expects Kerviel's "entire hierarchy" to eventually be questioned.