A federal judge in Los Angeles found former Nixon Peabody securities partner David Tamman guilty Tuesday of 10 criminal counts connected to his participation in a Ponzi scheme that bilked investors, primarily members of Los Angeles’s Iranian-Jewish community, out of as much as $20 million.

U.S. district court judge Philip Gutierrez’s decision capped a seven-day bench trial during which prosecutors laid out the evidence they said supported the charges of conspiracy, obstruction of justice, alteration of records, and accessory to mail fraud and securities violations handed up against Tamman by a federal grand jury last December.