It was a cash-for-favors sting operation that raised far more questions than it answered.

It began in 2010 when Republican Tom Corbett was attorney general and it targeted Democratic and Republican state lawmakers When it was brought to a halt by Corbett’s successor, Democrat Kathleen Kane, in 2013 it had reportedly snagged four lawmakers and a former traffic court judge -- all Democrats from Philadelphia.

At the time, Kane said she was shutting down the operation — even though the lawmakers were caught on tape accepting cash, gifts or money orders — because the investigation was too botched to prosecute. Among the concerns she cited were: 1) the informant who delivered the payouts — a lobbyist working undercover for the attorney general’s office — lacked credibility, and 2) unconventional law enforcement methods were used to build the case.

Last month, Seth Williams, Philadelphia district attorney, said his office empaneled a grand jury to revisit the case.

On Monday, activist Gene Stilp, who filed complaints against the four lawmakers with the Pennsylvania State Ethics Commission, said he received a letter from the ethics commission confirming it was conducting a full investigation.

Kane has repeatedly maintained she made the right decision, but questions about whether this case was abandoned for political reasons have not gone away.

This two-pronged approach — the grand jury and the ethics commission probe — should answer lingering questions.

Grand juries enjoy broad investigative powers. And while the ethics commission does not have the power to impose criminal penalties, it can fine public officials for violating state ethics laws and can refer cases to law enforcement for possible criminal charges.

This case has done nothing to bolster public confidence in our political system or a criminal justice system that should punish politicians when they break the law.

Together, the grand jury and the ethics commission have the power to hold these people accountable and to restore the public’s faith.