A state grand jury is investigating whether House Republicans used an expensive, tax-funded computer system for political purposes.

The Pennsylvania House Republican caucus paid tens of thousands of dollars in state money to build a computer program to catalog voters down to their individual precincts, including a list of new voters, and a clause requiring the caucus to provide staff to enter data for use in elections.

Within three years, the caucus was paying $1.8 million for a sophisticated database system that tracked information.

The contract, with Aristotle Inc., a Washington, D.C., data firm, is now the subject of a probe by a state grand jury. The jury has questioned current and former employees of former House Speaker John Perzel, R-Philadelphia.

A copy of the contract, obtained by the Pittsburgh Post-Gazette, contains a May 30, 2003, amendment to an older contract between the House Republicans and Aristotle, outlining an array of services that at points openly refer to elections. Pennsylvania law forbids the use of state funds or resources for campaign purposes.

The original contract between the House Republicans and Aristotle was signed in May 1996 by Mr. Perzel, then the majority leader. Mr. Perzel became House speaker in April 2003 but now has no leadership position in the Democratic-controlled House.

The amendment, signed by J. Anthony Painter, then director of Republican Information Technologies and later an official with Aristotle, calls for each House district in Pennsylvania to be created as a database "populated by data provided by the caucus" and available to caucus staff.

"The caucus will provide the necessary staff to provide for the proper editing of the address lists for all districts so that all districts will be properly loaded and ready for use in the elections," the amendment reads.

The contract leaves open the possibility that the data would be stored on caucus servers -- a state-owned computer system ostensibly used for constituent services by elected Republican representatives.

Other sections of the contract amendment call for Aristotle to develop a name lookup system "to offer the user assistance in the selection of valid wards and precincts" and a means to flag "out-of-district addresses."

The company and caucus officials did little to disguise the overtly political nature of the new database. "The Caucus will provide a list on a regular basis of updated voters," said one section, headed "Addition of New Voters."

Another section called for the Caucus to provide to Aristotle "on a regular basis, the full updated list of Pennsylvania voters to be loaded into the system. These records will be processed in the same manner as listed above in the Addition of New Voters section and treated as 'change' data."

Assorted "hot-key data" -- programs to allow the introduction of additional information with a single keystroke, included an example that seemed to suggest the listing of a voter willing to put up a candidate's yard sign.

The overall contract amendment indicated an initial price of $55,000. That is a fraction of the larger $1.87 million the caucus agreed to in January 2006. Among services purchased were an IP Telephony system that allowed legislative offices to track callers based on a nationwide voter database.

The House Republicans' connection with the firm began in late 1995 when Mr. Perzel arranged for the purchase of a program called CS!, or "Constituent Service!," a program advertised by the firm this way:

"Getting elected is only half the fun. Lots of people want your job. Constituent Service! helps you take care of the folks back home and make your next election easier."

After promising solutions for handling constituent mail and casework tracking, the company's Web site adds:

"Earning a reputation for uncompromising attention to constituent requests makes successive campaigns easier."

Prosecutors now want to know to what extent any of the data gathered from the casework files and subsequent $1.8 million contract might have found its way into the files created under the contract amendment calling for precinct-by-precinct voter data.

Last year, House Republican Leader Sam Smith, of Punxsutawney, drastically amended the Aristotle contract to eliminate large portions of the firm's work.

House Republican spokesman Steve Miskin said the caucus' database "was built from a list of registered voters obtained from the Department of State."

He said such information "is used to help [legislators] better respond to constituents. It helps identify and link constituents and concerns or issues more efficiently."

He said Mr. Smith didn't oversee the caucus's Information Technology Department until 2007, after Mr. Perzel was no longer speaker but merely a rank-and-file member.

"We understood the Aristotle contract is and was intended to assist members with constituent management," Mr. Miskin said.

However, the caucus has now decided to reduce costs, and "we have cut or eliminated most of our external contracts and are making better use of existing staff and resources," he said.

Mr. Perzel and officials at Aristotle could not be reached for comment.

Last month, six House Republican technology staff members were summoned before the grand jury and asked about the use of House computers and possible political work.

This week, Attorney General Tom Corbett, who is overseeing the investigation, reiterated an earlier statement that he would suspend any grand jury presentments or charges between Oct. 1 and Nov. 4 to avoid any effect on forthcoming elections.

In addition to the Aristotle contract, prosecutors have been considering a new round of charges against House Democratic officials and staff members for the destruction of computer and paper files connected to a criminal investigation into the use of state employees for political work during the 2004 and 2006 House election campaigns.

In July, former state Rep. Michael Veon, current state Rep. Sean Ramaley and 10 caucus staff members were charged after the grand jury determined they used state resources for campaign purposes.