State investigators and prosecutors went deep in their failed quest to show Sen. Don Balfour, R-Snellville, intentionally claimed bogus per diem and reimbursement payments from the state.

Along with Balfour’s reimbursement requests, investigators looked at the senator’s personal bank records, credit card statements, appointment calendars, emails, campaign contribution records, lobbyists disclosures and his Delta SkyMiles account.

The AJC reviewed thousands of pages of investigative documents and correspondence to determine how the attorney general’s office built the case, why the prosecution went flat or, indeed, why it went to court at all. Balfour was acquitted of all charges after a three-day trial in December.

Investigators dove into the several Atlanta condominiums Balfour has kept as a second residence, including leases, key card access data and car parking transponders.

In his return to the Senate Monday — he was suspended after the state indicted him — Balfour described the investigation as a monumental waste of taxpayer money on behalf of his political enemies.

“There should be a line between political gamesmanship and trying to destroy someone’s life and take their liberties away from them,” he said.

Ken Hodges, one of Balfour’s defense attorneys, described the state investigation into the long-serving Republican lawmaker as a “financial enema.”

While the metaphor is evocative, the inquiry into Balfour was not limited to finance. Investigators also were interested in who he was seeing.

“One more thing, can you please provide me with a list of allowed visitors?” GBI Agent Wesley Horne asked in an a November 2012 email to one property manager.

Investigators subpoenaed thousands of documents from the National Conference of State Legislators covering the time Balfour served as president. They downloaded his Facebook account.

None of this information was ever introduced at trial, where prosecutors from state Attorney General Sam Olens’ office instead relied upon a fairly straightforward approach of comparing Balfour’s per diem requests and mileage claims against his actual whereabouts.

It didn’t work.

Jurors did not buy that the 17 instances in which Balfour submitted inaccurate reimbursement requests were anything more than mistakes by a harried, but well-meaning, public servant.

Hodges, a Democrat who lost to Olens in the 2010 race for attorney general, said Olens was looking for campaign material for a future run for governor.

“I think he wanted to put Don Balfour’s head on the wall and be able to say, ‘I go after corrupt politicians,’” he said.

Hodges said he does not fault prosecutors for thoroughly investigating claims of political corruption. But they never should have prosecuted if they could not prove a crime had been committed, he said.

“When you dive deep and don’t find anything, don’t just make it up,” he said.

Olens’ office did not respond to a request for comment Monday.

Almost exactly a year out from Balfour’s December 2013 trial, the GBI produced an investigation report citing 106 days between 2007-2011 when Balfour received “questionable” reimbursements. By the time the case went to trial, the number had been whittled down to 17 reimbursements covering 39 days.

To win a conviction, prosecutors not only had to show that Balfour filed false reports but that he intended to do so. Nothing in the files reviewed by the AJC proved that the senator meant to seek reimbursements to which he was not entitled. Although the files reviewed by the AJC were voluminous, they did not include direct communications among state attorneys and other examples of “attorney work product.”

In a summary of a September 2012 meeting with Balfour and his attorneys, GBI agents told Balfour and his attorneys “they would be conducting a very basic yet thorough” investigation.

Communications between the lead investigator and prosecutors showed a confidence belied by the courtroom results.

“I believe we have a very strong case,” Horne said in a July 16, 2013 email to Assistant Attorney General Laura Pfister.

In the email, Horne was discussing information provided by Balfour’s attorneys showing dozens of cases in which the senator could have legitimately applied for reimbursement but did not.

“I do not mind reviewing and incorporating into our investigation, information from Senator Balfour’s attorney’s (sic) that they believe are helpful,” Horne wrote. But, he added, he did not want to “jeopardize the evidence” already collected against Balfour.

According to documents in the GBI file, Horne and the prosecutors were aware that Balfour’s defense team was conducting a parallel investigation using the same documents. Attorneys in Olens’ office disregarded the defense analysis.

“Wesley has plenty to go on without this stuff,” Pfister said of Horne in an email to Senior Assistant Attorney General David McLaughlin.

“This is all part of lawyer talk and negotiations,” McLaughlin replied. “Besides, because of our theory of the case, it doesn’t matter what he could have paid for.”

At trial, however, evidence of undercharging by Balfour was a powerful part of the defense, and prosecutors offered little rebuttal.