The remaining defendant in the conspiracy case involving the older brother of Providence Mayor David N. Cicilline is scheduled to go on trial next month in U.S. District Court in Boston.

Juan A. Giraldo, who is serving a six-year federal prison sentence for cocaine trafficking, will be tried on a felony charge that he conspired with lawyers John M. Cicilline and Joseph A. Bevilacqua Jr. to shake down a drug-dealing couple for $150,000 and manipulate the criminal-justice system.

Jury selection is set for Sept. 8, three days before Cicilline and Bevilacqua will be sentenced for their roles in the scheme. The lawyers, who pleaded guilty to criminal charges in June, each face about 20 months in prison. A fourth defendant in the case, Lisa Torres, of Providence, pleaded guilty to charges of conspiracy, obstruction of justice and making false statements. Torres, a former legal assistant for the lawyers, has agreed to spend 18 months in prison.

Judge Nathaniel M. Gorton will preside over Giraldo’s trial and will impose the sentences for Cicilline, Bevilacqua and Torres.

William M. White Jr., Giraldo’s Boston-based lawyer, said he has been negotiating with federal prosecutors in Boston.

“I don’t know whether there will be a trial or not,” he said. “We will just have to wait and see how things develop in the next few weeks.”

Giraldo, once an interpreter and paralegal for Cicilline and Bevilacqua, was close friends with both lawyers. A few years ago, Cicilline said he was interested in marketing a sports drink with Giraldo in Colombia.

The criminal case against Cicilline, Bevilacqua, Torres and Giraldo dates to 2002, when federal agents and local police seized more than $1.3 million in cash and nearly five pounds of marijuana from John C. Mendonca and his wife, Jacqueline. They were arrested outside a Motel 6 in Warwick and gave the authorities home addresses in Warwick and Fall River.

Once they were indicted in Boston, they hired Cicilline and Bevilacqua as lawyers. In November 2002, Bevilacqua met John Mendonca at the Plymouth (Mass.) County House of Correction and, according to the indictment, “told him that for a payment of several hundred thousand dollars, he … could keep John Mendonca out of jail.”

A month later, Bevilacqua and Giraldo met with Mendonca and told him that in return for an “up-front” payment of $100,000, they would give the authorities information that could lead to “a large drug bust,” information that they could attribute to the Mendoncas with the aim of getting them a reduced sentence.

When Bevilacqua and Giraldo failed to provide the information that the Mendoncas had paid for, Cicilline told the couple that for an additional $50,000 he would make sure that Bevilacqua and Giraldo made good on their promise.

They later lied to federal investigators about the arrangement.

Giraldo has been serving his federal drug sentence in Youngstown, Ohio. A few weeks ago, he was transferred to the Donald W. Wyatt Federal Detention Center, in Central Falls, to get ready for the trial in Boston.

bmalinow@projo.com