A French trader was ordered to be jailed Friday while investigations continue into the billions in losses he allegedly caused at Societe Generale bank.

A probe into the case broadened as well, with police taking into custody a brokerage employee who reportedly had been in contact with Jerome Kerviel, the 31-year-old futures trader.

Prosecutors sought to jail Kerviel to keep him from contacting accomplices, if he had any, and from jeopardizing what promises to be a long and complex investigation.

Judges allowed Kerviel to go free last month after his lawyer argued he did not pose a flight risk.

It was unclear if Kerveil had been taken into custody Friday.

News that police had arrested a second person, an employee at a brokerage arm of Societe Generale, again raised questions about whether Kerviel acted alone.

Societe Generale, one of France's biggest banks, has said Kerviel did not appear to have accomplices when he made massive unauthorized bets on European futures markets that the bank said cost it more than $7 billion to unwind.

The daily newspaper Le Monde reported Friday, however, that the bank has turned over new evidence, including a message sent to Kerviel through the bank's computer system by the broker now in custody.

The message, sent Nov. 30, read: "You have done nothing illegal in terms of the law," the newspaper reported.

The employee from brokerage Newedge, a 50-50 joint venture between Societe Generale and bank Calyon, was taken into custody Thursday and was still being held Friday, according to a judiciary official who asked not to be identified because of the sensitivity of the case.

Societe Generale spokeswoman Joelle Rosello confirmed the employee was in custody. "We are cooperating closely with police," she said.

Le Monde said Kerviel passed some trades through the brokerage, and that police suspect that the brokerage employee was aware of Kerviel's activities. It said the brokerage was searched Thursday.

Societe Generale announced Jan. 24 that it lost 4.82 billion euros ($7.09 billion) cleaning up Kerviel's unauthorized transactions. It said Kerviel overstepped his authority and bet 50 billion euros ($73 billion) -- more than the market value of the entire bank -- on futures in European equity markets. It also said he did not appear to have profited personally from the trades.

Since the scandal become public, Societe Generale has faced speculation that it could be bought out or broken up, and about how Kerviel's activities went unnoticed or ignored.

Investigating judges have filed preliminary charges against Kerviel for forgery, breach of trust and unauthorized computer activity.