How many more officials might face charges as the result of an ongoing investigation by state Attorney General Tom Corbett is not yet known. But with the first corruption-related charges having come down this week, most observers expect more — perhaps many more.

With yesterday's arraignment of former state Rep. Frank LaGrotta on felony charges of violating the state's conflict-of-interest law for adding relatives to his payroll as "ghost employees," the first shoe dropped in the Corbett probe. As the investigation continues and as more witnesses appear before a grand jury, people will be wondering how many more people will be implicated.

News that LaGrotta, who represented parts of northern and central Butler County, would be charged for putting relatives on the state payroll and paying them for work that was not done came on the same day that it was learned that House Majority Leader H. William DeWeese,D-Greene County, had fired seven staffers, including three who had held top positions in the Democratic House caucus.

Investigators have been looking into year-end bonuses paid to legislative staffers in late 2006 that appear to be linked to work performed on elections for legislative seats. Using taxpayer dollars to pay for political work is illegal, although the current probe suggests it might not be unusual in Harrisburg.

Corbett's investigation has focused primarily on House Democrats, who paid a stunning $1.9 million in bonuses in late 2006. That figure was four times higher than the bonus money paid out in 2005, a non-election year.

DeWeese, who also reportedly signed off on an agreement that backdated LaGrotta's sister's employment contract, has been reported as the author of a memo telling recipients of the big legislative bonuses not to talk about the "extraordinary" payments with anyone.

Reporters for a Pittsburgh newspaper found that 80 of the 100 largest bonuses went to people who had worked for, or contributed to, the campaigns of DeWeese, or former state Rep. Mike Veon, or the House Democratic caucus campaign committee.

Numerous Democratic staffers, and some Republicans, have been called before a grand jury to testify. It is expected to be a lengthy investigation.

While speaking to Corbett's investigators about evidence that he had put family members in state jobs and padded their pay, LaGrotta also provided information about how the legislative bonus system worked with House Democrats. After having been given immunity from prosecution on that issue, LaGrotta gave investigators an insider's view of the House Democratic leadership. LaGrotta reportedly told investigators that partisan political work was routinely done through the Office of Legislative Research.

And it was those offices that were the target of investigators in late August when 20 boxes of materials were seized.

With the evidence seized in the House Democratic research office and the testimony of LaGrotta, the investigation and coming prosecutions by Corbett's office could advance the reform movement launched by voters in the 2006 elections when a record number of incumbents were defeated, or chose not to run, for re-election.

Voters' wrath was fueled by the infamous middle-of-the-night pay-raise vote of July 2005 and later revelations about unvouchered expenses and law-making procedures that violate constitutional mandates. Since that time, voters have been demanding that the culture of entitlement and, in some cases, the culture of corruption, in Harrisburg, change.

But change has been slow, as reform-minded lawmakers, both those newly elected and a few incumbents, find their efforts blocked by many of the well-entrenched lawmakers who remain in Harrisburg and still wield great power.

The charges against LaGrotta represent the beginning of a prosecutor and courts-driven reform movement. The firings of the Democratic staffers by DeWeese can be seen as evidence that there will be many more shoes dropping in Corbett's investigation.

The mood in Harrisburg has to be one of fear, uncertainty and anxiety. For all Pennsylvanians, there should be satisfaction in the belief that lawmakers and other officials will be held accountable for their actions and their use of taxpayer dollars.

For voters, the courts might help advance the reform movement that was started in the 2006 election defeats of incumbents — and which hopefully will be resumed in the 2008 elections.