In announcing two more arrests in the resurrected sting investigation on Tuesday, Philadelphia District Attorney Seth Williams made clear that he expected convictions.

State Reps. Vanessa Lowery Brown and Ronald G. Waters, who are accused of taking money from an undercover operative, admitted their guilt when questioned by a grand jury, Williams said.

Brown, 48, and Waters, 64, both Democrats from West Philadelphia, "fully - and I repeat, fully - admitted to knowingly taking illegal cash payments," the district attorney said.

The two defendants turned themselves in to state police at the Harrisburg office of a district judge on Tuesday morning while Williams was detailing the case against them at his office in Philadelphia.

They were booked on charges of bribery, conflict of interest, conspiracy, and misdemeanor charges of failing to report the cash on their financial disclosure forms. Both were released on their own recognizance.

With the arrests, Williams, a Democrat, has brought charges against three Democratic officials from Philadelphia out of a total of five implicated in the sting.

Waters was negotiating with prosecutors in a bid to plead guilty to lesser charges, said his lawyer, Fortunato Perri Jr. Perri said Waters had "begun the process of accepting responsibility for his conduct."

Brown's lawyer, Luther E. Weaver 3d, declined to comment.

Williams would not discuss any plea negotiations, but said defendants who admit guilt before a grand jury often do so in the hope of making a case for more lenient punishment.

Thomasine Tynes, the former president judge of Traffic Court, who was the first person charged in the case, is scheduled to appear in court Wednesday to plead guilty to a conflict of interest charge. Bribery and other charges are to be dropped under the deal with Tynes, who is accused of accepting a $2,000 Tiffany bracelet from an undercover operative.

Williams said the investigative grand jury that recommended charges against Tynes, Brown, and Waters was still at work. That leaves a question about the fate of two other lawmakers who sources and investigative documents say were caught on tape accepting money, State Reps. Louise Williams Bishop and Michelle Brownlee.

Bishop took $1,500 from a lobbyist who was working as an undercover operative and Brownlee accepted $2,000, sources and documents say. Bishop has said she did not accept any money. Brownlee has said she could not recall accepting a payment.

Launched in 2010 by Republican Gov. Corbett when he was attorney general, the sting deployed a lobbyist, Tyron B. Ali, as an undercover agent who distributed cash and checks to the lawmakers and gave Tynes the bracelet.

Ali had been arrested on charges of defrauding a state program that feeds poor children and the elderly. He was working to win lenient treatment in that case.

Attorney General Kathleen G. Kane, a Democrat, inherited the case and shut it down in 2013. All records of the case were put under court seal.

After The Inquirer disclosed her decision this year, Kane denounced the probe as poorly conceived, badly managed, and possibly marred by racial targeting.

That criticism was rejected by Williams, who adopted the case after Kane effectively dared him to do so.

In a presentment made public Tuesday, the grand jury said Waters took $8,750 from Ali in nine payments.

After pocketing one payment of $1,000, Waters was captured on tape saying, "Happy birthday to Ron Waters."

First elected to his legislative seat 15 years ago, Waters has been a quiet backbencher in Harrisburg. Despite the news of the sting, he breezed to his ninth term in November. He had no opponent in either the primary or the general election.

Brown, too, easily won reelection, in her case, to a fourth two-year term. A more charismatic figure than Waters, she chairs the legislative Black Caucus.

If either were to be convicted of felonies, the state constitution requires them to resign their positions.

Brown, the grand jury said, accepted $4,000 from Ali. After one payment, the panel said, she was caught on tape asking, "What do you need me to do?"

Williams called the evidence against the two lawmakers "clear, convincing, and captured on tape."

He added, "I know both Ron Waters and Vanessa Brown personally. This is a sad day for them, for their constituents, and for this city."