PITTSBURGH — The prosecution in state Sen. Jane Orie's ongoing political corruption trial rested its case Thursday afternoon after 13 days of testimony from more than 30 witnesses.

Most of the witnesses were former staffers under Orie, and almost all testified to having conducted political and campaign work illegally while on the state's clock.

The state senator is charged with 26 felonies, including theft of services and violations of the state's Ethics Act. Those felonies include five counts of perjury and charges of forgery after Orie's first trial last March ended in a mistrial.

Prosecutors with the Allegheny County District Attorney's office called Joseph Stephens, an expert document analyst with the Secret Service, as their last witness to testify about the forged documents that caused the mistrial.

Stephens occupied the stand for about half of the day Thursday and broke down his analysis for the jury with a PowerPoint presentation.

Using highly technical procedures, Stephens in his analysis used a microscope to examine 136 documents that were submitted as evidence last year in Orie's first trial.

Perhaps his most important conclusion centered around a document authored in 2010 by Jamie Pavlot, Orie's former chief of staff. That authentic document detailed personal and vacation time taken by Pavlot during 2009.

Problems arose, Stephens testified, when he linked Pavlot's signature on that document to three other documents that were authored and created in 2006. Her signature on the 2010 document had clearly been copied and pasted or photocopied onto the others, he said.

Those earlier memos, which contained directives from Orie warning her staff not to engage in political work in the legislative office, were used to discredit Pavlot's testimony in the first trial because she testified to having never seen the documents despite the fact that her signature was allegedly on them.

Prosecutors alleged Orie forged the signatures sometime before the first trial in an effort to make it seem like Pavlot ignored repeated orders from her boss to bar political work on state time.

William Costopoulos, Orie's defense attorney, even acknowledged to the jury Thursday that Stephens “established beyond mathematical certainty” that the signatures are not authentic.

But he argued that prosecutors have absolutely no evidence linking his client to the forgeries.

“There is no way of determining forensically when this was done and who did it?” Costopoulos asked, to which Stephens replied there was not.

Stephens also focused his presentation on other documents that contained handwritten notations in the margins, such as one memo that scolded Pavlot and reminded her that “you are in charge and must enforce” the rules.

Under analysis, Stephens concluded that the ink used on 63 handwritten notations in question was readily available at the time of the document's origin, meaning there was no proof that Orie added the directives retroactively.

But that doesn't exonerate Orie or suggest the notations are authentic, the analyst warned.

“Actually some of the documents dated over many years contained the same ink,” he said. “That's typically a sign that the notations were added all at the same time or over some time with the same pen.”

As his first defense witness, Costopoulos called upon a forensic accountant to debunk claims made Wednesday that Orie benefited to the tune of $341,000 by forcing her state-paid staff to work on political tasks.

A forensic accountant presented by the prosecution also alleged that Orie stole more than $34,000 from the state by using senate-owned computers and printers for her campaign activity.

Ken McCrory, classified as an expert witness, said that the methods used by Jackie Weibel, the district attorney's accountant, “failed virtually every accounting standards that exist.”

McCrory lambasted Weibel's procedures, saying they were based more on distant memories of staffers rather than objective facts. Weibel compiled her estimations by sitting in the courtroom and listening to percentages offered by each former staffer about how much time they spent on political tasks.

“Those percentages came from people who were stressed and scared,” McCrory said. “And they were asked to remember distant memories. It's like asking how long you mowed the lawn for in 2001. They have no idea.”

Deputy District Attorney Lawrence Claus, however, asked McCrory to read part of a transcript of his testimony given at least year's trial.

His argument and testimony was nearly identical to the testimony he gave Thursday, despite the fact that a different forensic accountant last year testified for prosecutors and gave a different calculation.

Costopoulos was to continue with the defense's case today. The jury is expected to start deliberations on the case by the middle of next week.