CHICAGO (AP) — Conrad Black, a once-powerful media mogul whose newspaper empire spanned several continents, is headed back to prison after a federal judge ruled Friday that he had not served enough time for defrauding investors.

US Judge Amy St. Eve sentenced Black to 3 1/2 years in prison, but prosecutors say he will be given credit for the about two years he already had served. The resentencing came after an appeals court decision last year.

Black’s wife, Barbara, seated on a courtroom bench, collapsed into the laps of other spectators as the sentence was delivered, and medics were called to attend to her.

Black had addressed the judge for about 20 minutes before the sentence was imposed. He did not concede any guilt.

“I never ask for mercy,” he said, standing with his hands on the podium and looking at the judge, “but I do ask for avoidance of injustice.”

Prosecutors who brought the fraud case against Black, 66, had depicted him as a devil-may-care elitist who looks down his nose at the rest of humanity. The defense counters he is a gentleman unbowed by adversity, who quietly goes about helping others.

A jury convicted Black in 2007, and at the time St. Eve at the time sentenced him to 6 1/2 years for defrauding investors in Hollinger International Inc.

But Black, whose empire once included the Chicago Sun-Times, The Daily Telegraph of London, The Jerusalem Post and small papers across the US and Canada, was freed on bail after serving two years to let him to pursue what would be partially successful appeals.

The 7th US Circuit Court of Appeals in Chicago last year tossed out two of Black’s fraud convictions but upheld a conviction for fraud and one for obstruction of justice. And it said St. Eve would have to sentence Black again for those two standing counts.

Despite the nullified counts, prosecutors had asked St. Eve to hand Black the same 6 1/2-year sentence she originally meted out in 2007, meaning he would have had to spend about 4 1/2 more years in prison.

“He fails to acknowledge his central role in destroying Hollinger International through greed and lies, instead blaming the government and others for what he describes as an unjust persecution,” prosecutors said in a recent filing.

Black’s lawyers, in turn, have accused government attorneys of vindictiveness, saying their justification for a stiffer sentence displays “a drive-by disparagement of Mr. Black which reveals nothing but the intensity of the government’s dislike for him.”

The defense argues Black was a model prisoner, noting that the accomplished biographer — whose subjects have included Franklin D. Roosevelt and Richard Nixon — helped teach inmates American history and economics; and gladly offered advice about business and other matters to prisoners who constantly approached him.

But prosecutors say the defense paints too rosy a picture of Black’s prison life.

One prison employee, Tammy Padgett, claimed in an affidavit filed by prosecutors that Black had arranged for inmates — “acting like servants” — to clean and cook for him, to iron his clothes, mop his floor and perform other chores.

Another employee told her that Black once insisted that she address him as “Lord Black,” after an honorary title bestowed on him by Britain, Padgett added.

The defense denied both characterizations.

His big chance to squash the convictions arose in June of 2010, when the US Supreme Court sharply curtailed disputed “honest services” laws that underpinned part of Black’s case. The appellate court that reversed two of Black’s convictions cited that landmark ruling.

But the appellate judges said the one fraud and obstruction of justice convictions were not affected by the Supreme Court’s ruling. The fraud conviction, the judges concluded, involved Black and others taking US$600,000 and had nothing to do with honest services: It was, they asserted, straightforward theft.