WASHINGTON — Deborah Jeane Palfrey was convicted yesterday afternoon of racketeering and other charges after a federal court jury determined that her upscale escort service was actually a front for prostitution.

Jurors deliberated less than eight hours before returning the verdicts against Palfrey, 52, who stood impassively, with her hands folded in front of her, as the decision was read. She will remain free pending her sentencing July 24. Assistant U.S. Attorney Catherine Connelly urged U.S. District Judge James Robertson to lock Palfrey up immediately, arguing that the verdict will give the woman dubbed the D.C. Madam a motive to flee. But the judge, noting that Palfrey has never missed a court appearance, denied the request.

The jury heard four days of often tawdry testimony from employees and clients of Pamela Martin & Associates, the business that Palfrey ran until 2006. Palfrey, who has repeatedly denied any wrongdoing, did not testify. The jury convicted her of all charges: one count of racketeering, two of using the mail for illegal purposes, and one of money laundering.

In closing arguments, Assistant U.S. Attorney Daniel Butler argued that the government’s evidence, including testimony from 13 former call girls, proved that sex-for-money was the real business of the $250-an-hour D.C. escort service that Palfrey ran by phone from her Northern California home. He rejected defense claims that Palfrey did not sanction illegal acts and that the business offered legal sexual game-playing and fantasy.

An IRS agent said the business generated about $2 million in revenue, which Palfrey and the escorts split about evenly.

Most of the 13 former escorts testified that Palfrey was careful not to talk about prostitution explicitly with them. The women said, however, that they discussed the subject many times with Palfrey in veiled terms and that they understood that she would not employ them unless they engaged in paid sex acts with clients.

Three former clients, a landscaper and two lawyers, also testified that Palfrey ran a call-girl service. Each said he had sex with escorts dozens of times.

The defense contended that the escorts and clients decided to engage in sex acts without Palfrey’s knowledge. “My client did not have an intent to provide illegal activity,” the defense lawyer, Preston Burton, told jurors in closing arguments yesterday.

At the start of the trial, Mr. Burton’s witness list included two prominent men, both linked to Palfrey’s escort business through phone records: Senator Vitter, a Republican of Louisiana, who apologized to his constituents for an unspecified “very serious sin” after his name surfaced in the case in July; and Randall Tobias, who resigned as a deputy secretary of state last April after acknowledging that he had used Palfrey’s service for massages. But neither of them was called to testify.

At least 132 women were employed by the firm in the Washington area between 1993 and 2006, and their names appeared on money orders and other documents submitted by the prosecution during the trial. The judge yesterday sealed records that would identify those women who did not testify.