HARRISBURG - Another Democratic state legislator from Philadelphia has pleaded guilty to corruption charges in the resurrected sting investigation.

Rep. Michelle Brownlee pleaded guilty Monday to one count of violating the state's conflict-of-interest law and was immediately sentenced to 18 months' probation. As required by the state constitution, she resigned her seat upon sentencing, but she will more than likely be allowed to keep her pension.

Brownlee, charged with accepting $2,000 in cash from a lobbyist working as an undercover operative, was silent during her appearance in Dauphin County Court. She and her lawyer, Mia Perez, declined to comment afterward.

In court, Perez told Judge Scott Evans that Brownlee's life "has been about serving the state."

With Monday's plea, four of six public officials implicated in the sting, all Philadelphia Democrats, have pleaded guilty in connection with the investigation, in which the confidential informant offered cash or money orders in exchange for official favors.

The case was revived last summer by Philadelphia District Attorney Seth Williams after Attorney General Kathleen G. Kane shut it down. As The Inquirer first reported last year, Kane, a Democrat, secretly ended the sting operation in 2013 without bringing criminal charges.

She said the investigation was poorly handled, and marred by possible racial targeting and a lack of a clear quid pro quo for the payments. She said she had evidence that the undercover operative, Tyron B. Ali, had been ordered to focus only on African American targets.

Assistant District Attorney Mark Gilson, who, with city prosecutor Brad Bender, has led the reinvestigation of the sting, has said he found no evidence of racial profiling in the case.

Brownlee, 58, was charged this year with bribery and other crimes for pocketing $2,000 in 2011 from Ali. He handed her the cash, which he had wrapped in a napkin, as the two went for a walk before dinner in Harrisburg.

In their final meeting, Brownlee told Ali that her votes had to reflect her district's wishes on certain key issues, but on others, she said, she could "vote any freaking way I want to vote."

First elected five years ago, Brownlee represented the 195th District, which includes parts of Fairmount, Spring Garden, and West Philadelphia. She faced no opposition in last's year primary or general election. Before wining the seat, she served for many years on the staff of her predecessor.

When Inquirer reporters asked Brownlee about the sting last year, she said she had dined with Ali, but added: "I don't recall taking any money from him."

Williams' plea offer to Brownlee was consistent with offers he made to other defendants in the case: They could keep their government pensions and avoid prison, but their guilty pleas would mean they would have to resign from office.

Under the carefully tailored pleas, Williams dropped bribery charges - conviction on which would, by law, trigger the loss of the state pensions. The felony charge to which Brownlee and the others pleaded guilty - violating the conflict-of-interest law - does not trigger that provision.

The state law governing loss of pensions for corruption specifies that only certain offenses dictate forfeiture of retirement benefits.

Brownlee has to pay $2,000 to the Attorney General's Office, covering the money she accepted, and also $3,500 to the Philadelphia District Attorney's Office for the cost of prosecution.

Last Monday, former State Reps. Ronald Waters, 65, and Harold James, 72, pleaded guilty to conflict-of-interest charges. State Rep. Vanessa Lowery Brown, 48, had also been expected to admit guilt in the sting that day, but had second thoughts, according to prosecutors. She is scheduled to face another hearing next month.

State Rep. Louise Bishop, 81, is fighting the charges, arguing that the racial issues mentioned by Kane meant that she was a target of unfairly selective prosecution.

The first to plead guilty in the sting case was Thomasine Tynes, 72, a former Traffic Court judge. Tynes accepted a $2,000 Tiffany bracelet from Ali and was sentenced last year to 23 months in prison.

That term is concurrent with a two-year federal prison term she is serving in an unrelated ticket-fixing case.