New York ? Frank Quattrone, a star investment banker during the Internet stock bubble, was convicted Monday of obstructing justice for sending a 22-word e-mail encouraging the destruction of files while a criminal probe of his bank was under way.

A federal jury in New York deliberated about seven hours during two days before returning the verdict, which will likely send Quattrone to prison.

The defense planned to appeal, citing “an awful lot of evidence” that was kept away from the jury.

Quattrone, who took the witness stand in his own defense last week, stood stone-faced as the verdict was delivered, then turned to hug his mother, who burst into tears. He did not address reporters.

It was the second trial for Quattrone on charges of obstructing a grand jury, obstructing federal regulators and witness tampering. The first ended in a hung jury in October.

The case was the second consecutive big win for New York federal prosecutors in their pursuit of white-collar crime, coming just two months after Martha Stewart was found guilty of lying about a stock sale. Both Stewart and Quattrone were charged with obstructing investigations in which they were not charged with the underlying crime.

In addition, prosecutors have wrung guilty pleas from an array of other corporate stars, including high-ranking former executives of WorldCom Inc., Enron Corp. and ImClone Systems.

“When we learn of efforts to obstruct or interfere with those investigations, we must, and we will, prosecute those cases to the fullest extent permitted by the law,” U.S. Atty. David Kelley said.

The Quattrone case turned on his response to a Dec. 4, 2000, e-mail from Credit Suisse First Boston banker Richard Char that encouraged investment bankers to “clean up those files” before the holidays.

Former star investment banker Frank Quattrone, left, leaves New York Federal Court with his attorney John Keker. He was found guilty Monday of all counts in his retrial for obstructing a grand jury, obstructing federal regulators and witness tampering.

The next day, Quattrone sent a 22-word reply to the bankers, citing his own experience as a key witness in a securities trial and adding, “I strongly advise you to follow these procedures.”

Quattrone said it was a simple endorsement of company policy, which called for regular discarding of outdated files.

But the government contended the reply amounted to obstruction because Quattrone had been told two days earlier by a high-ranking CSFB lawyer that the bank was the subject of a criminal investigation.

A grand jury and the Securities and Exchange Commission were looking into how the bank had allocated shares of hot initial public offerings of stock during the Internet boom.

Quattrone maintained that he believed the investigation was limited to whether hedge funds had paid suspiciously high fees to get in on sought-after stock allocations — decisions he said were made by other parts of the bank.

But hours before returning the verdict, jurors asked to hear a readback of Quattrone’s testimony about his involvement as a witness in a 1991 securities trial in Texas.

“He was too well-aware of what was going on to let that slip his mind,” said juror Sheldon Silver, 58, a receptionist for a public relations firm.

U.S. District Judge Richard Owen set sentencing for Sept. 8. Quattrone likely will receive from 10 to 16 months in prison.

Quattrone’s lawyer, John W. Keker, said he was “obviously grossly disappointed.”

“I feel like we failed Frank,” he said outside the courthouse. “He’s innocent. There’s an awful lot of evidence that the jury didn’t hear. Perhaps if they heard it they would have reacted differently.”

His comments were an apparent reference to repeated decisions by Owen to keep certain evidence that defense lawyers wanted to introduce away from the jury.

Among the papers Keker wanted introduced were memos by internal CSFB lawyers that the defense claimed showed Quattrone was not made aware of the scope of the investigation in 2000.

After the first trial, Keker filed a motion seeking to have Owen remove himself from the case, citing a pro-government bias. The judge declined.

The trial featured near-constant sparring between Keker and the judge. Keker claimed during cross-examination of Quattrone that Owen was not letting him finish answers, and the judge frequently waved off Keker’s objections.

Quattrone rose to stardom in the banking industry in the late 1990s, while dot-com stocks boomed. He took technology companies like Amazon.com and Netscape Communications Corp. public and made $120 million at CSFB in 2000.

By late 2000, the government was looking into whether some CSFB clients had paid excessive commissions — essentially kickbacks — in exchange for getting a piece of hot IPOs.

Exactly what role Quattrone played in those stock allocations became a central issue at the retrial — particularly when he took the gamble of testifying in his own defense.

Under questioning from Keker, Quattrone said he had some input into who received IPO shares but insisted he made no final decisions on allocation.

“What I thought the investigation was about was hedge funds paying excessively high commissions to get IPO allocations,” Quattrone testified.

In a six-hour cross-examination, prosecutor David Anders displayed a series of e-mails designed to show Quattrone was intimately involved in how the bank allocated IPO shares.

In one exchange, Quattrone and CSFB brokers debate how many shares of a new IPO, AvantGo, should be doled out to Research in Motion CEO Jim Balsillie, who did business with the bank.

“Would like to be on generous side of what can be defended,” Quattrone wrote.