Conrad Black, the former Hollinger International Inc. chairman, didn’t receive a fair trial before he was jailed for fraud and obstruction of justice, his lawyer told a three-judge panel of a U.S. appeals court.

Arguing for a reversal of Black’s conviction last year, attorney Andrew Frey yesterday told the Chicago-based court that U.S. District Judge Amy St. Eve gave bad advice to the jury on how it should weigh the evidence it heard.

“I think this is the weakest case that I’ve seen in 45 years of law practice,” Mr. Frey said.

Black, 63, helped found the Chicago-based company now known as the Sun-Times Media Group Inc., working with its former president, F. David Radler, to create what was once the world’s third-largest English-language newspaper publisher.

A jury last year found him and three other former Hollinger officials guilty of stealing $6.1 million from the company as they engineered its sale of more than $3 billion in assets. On March 3, Black, a member of the British House of Lords, began serving a 6 1/2-year prison sentence at an American prison in Coleman, Florida.

Prosecutors have argued they produced sufficient proof to sustain the conviction of Black and his co-defendants.

The defendants misused the “substantial authority and discretion” they possessed as Hollinger’s top officers, Assistant U.S. Attorney Edward Siskel told the appellate panel.