The junior financial trader accused of making huge unauthorized trades leading to a loss of 4.9 billion euros ($7.1 billion) at France's Societe Generale Bank was being held in police custody in Paris on Saturday for questioning, according to reports.

Jerome Kerviel, 31, was being held at offices of the financial police in the southeast part of the city. He can only be held for up to 24 hours but can be extended another day. He was driven into the financial brigade's headquarters at 2 p.m., Bloomberg reported.

Police visited the offices of Societe Generale yesterday, looking over computer data and records, according to Reuters.

An attorney at the law office representing Kerviel said Thursday that the trader was ready to speak with authorities, and was not on the run, according to reports.

Kerviel, who earned 100,000 euros ($145,000) annually, is blamed by bank officials for carrying out fake deals and overcoming high security controls. The bank questioned him about his trades last Saturday.

Bank officials said he did not earn anything from the trades, and seemed to do it on his own, according to company officials.

Kerviel, who began working at the bank in 2000, was previously employed at Societe's risk management office where the company monitored trades. The company said that the knowledge he gained there aided his efforts to hide his trades.

After several months of trading, one of Kerviel's trades alerted the company that something was wrong. Several of the trader's supervisors will be fired, the bank said.

The company learned about problems with trades the Friday before last, and the next day it determined they were fraudulent. Over the course of the next week, starting on Monday, the company moved to unwind trading positions related to Kerviel's trades.

The trader's losses were about 2.9 billion euros, with another 2 billion euros spent to unwind the trades.

He focused on trades of baskets such as the Euro Stoxx 50 and in markets such as France's CAC-40 and Germany's DAX index.