When a Chicago prostitute and her pimp traveled to Pittsburgh to meet up with a new business partner, they expected to make a lot of money.

The business partner, who, they said, operated out of a house on Olympia Street on Mount Washington, proposed a 50-50 split. Displeased with the deal, they hatched a plan to kidnap her and recover the money they felt they lost.

Yesterday in federal court, the jury trial for one of the men accused of participating in the scheme began before U.S. District Judge Arthur J. Schwab.

Cornelius Newbern, 56, is charged with carjacking and interstate transportation in aid of racketeering. The prostitute, Danielle Scalzitti, 20, and her pimp, Andrew Pearson, have already pleaded guilty in the case.

According to Assistant U.S. Attorney Craig Haller, Mr. Newbern drove with Ms. Scalzitti and Mr. Pearson from Chicago on Dec. 6, 2007.

Mr. Pearson and Ms. Scalzitti had come to Pittsburgh to work with a woman named Paula Washington earlier that year. But after just a day or two, when she proposed a 50-50 split on Ms. Scalzitti's appointments, the two went back to Chicago.

"[Mr. Pearson] came up with a plan to come back and get what he thought he was owed from that first trip to Pittsburgh," Mr. Haller told the jury in his opening statement.

Mr. Newbern helped out by renting a red Chevy Cobalt and arranging to have two guns for the trip, Mr. Haller said.

Mr. Newbern's federal public defender said during her opening that her client knew nothing of the attack plan and instead came to Pittsburgh to try to shop his art portfolio to local museums.

"This is a case about trust and betrayal," said Elisa A. Long. "He saw it as an opportunity in a different city. But Mr. Pearson betrayed him. He duped him and deceived him."

But Ms. Scalzitti, an admitted drug addict, said that Mr. Newbern knew exactly what was going to happen in Pittsburgh and that he participated in the conversations to plan the attack.

On Dec. 7, Ms. Scalzitti lured Ms. Washington into the Olympia Street apartment, where Mr. Pearson attacked her, Ms. Scalzitti testified yesterday.

She told the jury that Mr. Pearson pistol-whipped Ms. Washington and that when Mr. Newbern walked into the room, he stopped Mr. Pearson from continuing the beating.

Then, Ms. Scalzitti said she duct-taped Ms. Washington's hands behind her back, and they put her in the woman's black Mercedes and drove it to her home in Westmoreland County. Mr. Newbern followed behind in the rented car, Ms. Scalzitti said.

The plan was to meet Ms. Washington's husband to collect money from him, although no specific amount was mentioned in court. However, before that could happen, Ms. Washington was able to work her way out of the duct tape and escape.

She was later flown by a medical helicopter to Pittsburgh for treatment of her facial injuries.

Ms. Scalzitti was arrested in Chicago a month later. She pleaded guilty in Allegheny County Court of Common Pleas to robbery and kidnapping and was sentenced to 21/2 to five years in prison.

Mr. Pearson and Mr. Newbern also were charged in state court in January 2008. They were indicted on federal charges in August of that year.

Mr. Pearson, who is scheduled to testify against Mr. Newbern, pleaded guilty earlier this month to interstate travel to aid in racketeering. He will be sentenced in December.

The case resumes this morning with Ms. Scalzitti still on the stand.