[JURIST] Lawyers for former star investment banker Frank Quattrone asked an appeals court Tuesday to throw out his conviction [JURIST report] due to confusing jury instructions given at his trial. Quattrone, sentenced to 18 months in prison [JURIST report], was convicted on charges [indictment, PDF text] of obstructing a federal stock investigation after he sent out an e-mail to employees at Credit Suisse First Boston [corporate website] that instructed them to "clean out their files." Quattrone's lawyer, Mark Pomerantz, argued that when the judge told jurors to find that Quattrone directed workers to destroy files that were subpoenaed for a federal jury trial, he did not order the jurors to recognize whether Quattrone knew that the documents that were destroyed were subpoenaed documents, as the bank regularly destroyed outdated documents. AP has more.