Frank Quattrone, the former star technology banker convicted earlier this month of obstructing justice, is seeking a new trial based on "unorthodox and confusing" jury instructions.
U.S. District Judge Richard Owen misled jurors about the legal standards the government was required to meet in order to find the ex-banker guilty," lawyers for Quattrone said Tuesday in court papers.
"These errors were highly prejudicial to the defense and seriously compromised the fairness of the trial," the papers said.
Federal prosecutors did not immediately return a call for comment on the motion. They will have a chance to respond to the papers before Owen decides whether to grant a new trial.
Quattrone, among the best-known investment bankers of the late-1990s technology stock boom, was convicted May 3 of obstructing a federal probe into stock allocation at his bank, Credit Suisse First Boston.
The case hinged on a 22-word e-mail Quattrone sent to subordinates at the bank on Dec. 5, 2000, suggesting bankers should "clean up those files."
In particular, Quattrone lawyers objected to a portion of the judge's instruction to jurors in which he explained the concept of "reasonable doubt" about the guilt of a defendant.
Owen said at the time that it was "practically impossible for a person to be absolutely and completely convicted of any controverted fact which by its nature cannot be proved by mathematical certainty."
The judge also said jurors should convict if they had "an abiding conviction as to the guilt of the defendant." The court papers also noted Owen had rejected language for requested by the defense.
Defense lawyers included accounts of comments made by several jurors to news organizations, including The Associated Press, that the defense said showed jurors improperly "filled in gaps" in the government's case.
In one story, a juror said he had voted to convict despite having "certain doubts." In another, a juror said it was difficult to gauge Quattrone's state of mind when he sent the e-mail.
The news accounts show jurors relied "simply on Mr. Quattrone's position as a senior manager or his intelligence, and speculation about what he must have or should have known," the court papers said.
The conviction came in Quattrone's second trial on charges related to the e-mail. The first ended in a mistrial last October, with jurors deadlocked on the same charges.
In papers filed previously, lawyers for Quattrone have accused the judge of having a pro-government bias. They also have the option of appealing the verdict to a federal appeals court later.
Quattrone, 48, is to be sentenced in September. Under federal sentencing guidelines, he could get more than a year in prison on his convictions for obstruction and witness tampering.