Second trader is released in France after questioning

Hopes of a rapid breakthrough in the French rogue trading scandal were dashed at the weekend when a friend and fellow trader of the €5bn man Jérôme Kerviel was released after two days of questioning.

Two investigating judges decided that there was no evidence that Moussa Bakir, 32, had helped M. Kerviel to build his €50bn mountain of unauthorised trades at the French bank, Société Gé*érale.

M. Bakir, a trader at a brokerage partly owned by SocGen, is now an "assisted witness" in the case – less than a suspect but still regarded as someone who can help investigators to untangle the Kerviel affair.

Further details emerged at the weekend of hundreds of instant electronic messages which passed between the two men in the last 12 months. At one point, the two men joked about M. Kerviel going to "jail".

The two traders were friends and M. Bakir handled many of M. Kerviel's purchases on the European market for shares futures. Investigators have sifted through 2,000 pages of transcripts of internal electronic messages, or chat, between the traders.

One exchange, on 13 December – revealed at the weekend – went as follows.

Bakir: "You absolutely need to take a holiday."

Kerviel: "In jail".

Bakir: "Don't be ridiculous. What have you done wrong? You have done nothing illegal as far as the law is concerned."

Kerviel: "I have maxed out on profits. That's all. That will show them the power of Kerviel."

M. Kerviel has insisted to investigators that he acted alone but has suggested that SocGen turned a "blind eye" to his immense unauthorised trades while he was making a profit. He claims that the bank should, therefore, carry part of the blame for his losses of €4.82bn, the largest ever to be incurred by a single rogue trader.

Prosecutors wanted M. Bakir to be placed under investigation for "conspiracy" but the investigating magistrates running the case decided that there was insufficient evidence. They are expected to question M. Bakir further this week.

His lawyer, Maître Jean-David Scemama, said: "My client explained perfectly well that he had respected all the rules... all the trades that he handled were authorised by his superiors and, I might almost say, encouraged."

M. Kerviel, who is back in custody, is under investigation for forgery, breach of trust and computer-hacking.