HARRISBURG - A House intern says he spent part of a summer two years ago erasing computer hard drives and destroying e-mail backup tapes that were later sought as part of the state attorney general's investigation into the legislative payroll bonus scandal.

That account and several others are detailed in an investigation report that gives day-by-day progress in the case that later became known as Bonusgate. The report was attached to a pretrial motion filed Monday by one of the 12 defendants in the case. While lengthy sections are blacked out, the Post-Gazette obtained a complete copy of the document, which offers glimpses inside the still-unfolding case.

At points, agents from the office of Attorney General Tom Corbett engaged in a cat-and-mouse pursuit of some top House staff members, subpoenaing surveillance videotapes that showed one rolling a cart of computers out of his office and into a parking garage. At another juncture, agents investigating former Rep. Mike Veon (D., Beaver) also turned their attention to an authority in the district of former House Majority Leader Bill DeWeese. Investigators subpoenaed records from the Greene County Industrial Development Authority, but apparently found nothing out of order.

The portions of the document kept out of the public eye sketch a series of incidents that suggest a scramble to erase evidence as the probe into the bonus scandal got under way. Prosecutors were able to recover only a handful of e-mails from the House Democratic Caucus in their investigation, and an account given by Tyrrell S. Drew, of Mount Holly, Dauphin County, a former intern in the Democratic Department of Information Technology, suggests why.

Drew, then a student at Harrisburg Community College, interned at the department from December 2006 through April 2007, and again from August 2007 to January 2008.

Interviewed by agents in January 2008, Drew said he was instructed to take five computer hard drives to another Capitol office and erase them with a large magnet. Drew said he was told by Steve Keefer, then the director of the office, "that the process would clean the hard drives so they could be reused. Drew explained to [state investigators] that it is his personal belief that a magnet as strong as the one he used would completely destroy a hard drive."

When Drew brought the hard drives back to the office, he said he encountered a worried reaction from Darryl Hazelwood, Keefer's deputy.

Drew said "Hazelwood went to Keefer's office - in a panic - and reported the hard drives were not completely erased," according to the report.

Drew said he was sent back to complete the erasures.

Hazelwood yesterday said he could not discuss the incident.

"Right now is probably not the best time to discuss those topics because there's still an ongoing investigation," he said.

Between February and April 2007, Drew told agents, he was instructed by another Department of Information Technology administrator to run a hand drill through e-mail backup tapes.

With backup tapes gone, investigators were stymied for a time in their attempt to establish a direct link between millions of dollars in year-end bonuses paid to House Democratic employees and their work in the 2006 campaign that gave their party control of the state House.

According to the report, investigators were also told that computers were taken from the Capitol building.