French trader Jerome Kerviel, accused by his former bank Societe Generale of causing a $4.9 billion euro ($7.2 billion) loss, is again in police custody as another trader is questioned to see if there is a link to alleged unauthorized deals.

A court in Paris reversed a decision to let the 31-year old junior trader free during the investigation. The court was concerned that Kerviel could try to flee or contact any possible accomplices.

Kerviel is in La Sante prison near central Paris, according to reports.

Media sources are also questioning a second trader, Moussa Bakir of brokerage Fimat, which has recently become a part of Newedge. He executed trades on behalf of Kerviel.

Until now, bank officials and Kerviel have maintained that he singlehandedly made trades at the bank.

The court has already charged Kerviel with breach of trust, forgery and hacking into computer systems. Prosecutors had considered also charging him with attempted fraud but there was not enough evidence to suggest he stole money from the bank.