Jerry Pratt went on and on about how he's turned his life around since his youth when he was arrested several times for fraud and property crimes.

He recently had a son. He's engaged to be married. He has a job as an assistant property manager.

And when he pretended to be a federal prosecutor last year to get a promotion, he didn't even know what he'd done was a crime, he told U.S. District Judge David S. Cercone.

"I absolutely had no malicious intent at all," said Mr. Pratt, 34.

But Judge Cercone stopped him, "It's a fundamental precept of the law: Ignorance of the law is no excuse."

The defendant said he understood. But still, he continued, he even called Assistant U. S. Attorney Ross Lenhardt to apologize immediately after getting a call from a federal agent telling him that impersonating Mr. Lenhardt was a crime.

In trying to persuade Judge Cercone to keep him out of prison, Mr. Pratt said he was a "fantastic father," and that his family needs his income to make ends meet.

Finally, Judge Cercone cut him off and asked the prosecutor if he had a sentencing recommendation.

Assistant U.S. Attorney Stephen R. Kaufman simply asked for a sentence within the guideline range: a combination of four to 10 months in prison, and/or a term of probation or house arrest.

"I think it's counterproductive to incarcerate him and make him lose his job," the judge said.

Instead, he ordered Mr. Pratt to serve four months home detention, and a total of three years' probation.

"What Mr. Pratt did was incredibly stupid, incredibly foolish," said Stephen Israel, his defense attorney. But, he continued, that doesn't mean he should go to prison.