Under the scrutiny of criminal investigators, election workers in Phoenix have spent the past week in a painstaking recount of 120,821 ballots that were cast three years ago for a Pima County transit tax.

The primary objective is to determine whether someone rigged the election by tampering with the optical-scan polling machines in Pima County, transforming "no" votes into "yes" votes.

The ballot measures wound up securing a half-cent increase in sales tax to provide cash for roads, buses and other transportation projects.

But ramifications of the ballot review may be even bigger than the $2.1 billion spending package: Voting machines in Pima County, which includes Tucson, are similar to those used in 12 of Arizona's 15 counties and in hundreds of jurisdictions across the country.

If it turns out the election was rigged by manipulating the computer programs, some fear, it will show weaknesses in electronic balloting that could endanger the democratic process.

Independent analysts and academic experts already have assailed Diebold Elections Systems, now known as Premier Election Solutions Inc., which manufactured the devices used in Tucson. They contend the electronic-voting machines are ripe for fraud.

And, no matter what happens with the recount, state Attorney General Terry Goddard said he is convinced the equipment jeopardizes election integrity.

"These (Premier) systems are very, very bad," Goddard said. "(They) are not state of the art in terms of security. They are not state of the art in terms of transparency."

Chris Riggall, a spokesman for Premier, said his company uses the most advanced technology available and urges clients to establish security protocols. Although there are internal safety features to prevent and detect tampering, Riggall added, those must be supported by external controls over election workers who handle the equipment.

"You can manipulate any voting system devised by man," he said, noting that even paper ballots are subject to fraud.

The Premier machines tabulate elections in about 1,700 U.S. cities, counties, states and other jurisdictions. Riggall said Pima County has a GEMS mainframe linked to AccuVote TSX touch-screen voting terminals. Grand jurors are reviewing allegations that an election technician in Tucson tampered with software, reversing the outcome of a funding vote for Pima County's Regional Transportation Authority.

Premier's machines showed a 60 percent vote in favor of a measure for the transit plan and 58 percent in favor of another measure imposing a half-cent sales-tax increase.

Officials with the Democratic and Libertarian parties alleged the financing measure, which failed four times previously and was far behind in pre-election polls, succeeded in 2006 because of fraud.

During an initial investigation, the Attorney General's Office hired an independent company to analyze the machines. Experts at iBeta Software Quality Assurance found a number of "irregularities" and determined that the Premier system had "fundamental security flaws."

They reported that a trained technician could have altered the vote and removed all evidence of the crime. However, they concluded that human error was a more likely culprit than fraud because evidence of tampering had not been erased.

The Attorney General's Office dropped the case in 2007, but the Democratic and Libertarian parties continued private investigations and filed lawsuits for election records against the Pima County Board of Supervisors, whose members all endorsed the RTA measure. During the case, county lawyers complained in a brief that they could not put up an adequate defense because of a concern that every employee who worked on the election computer might assert a Fifth Amendment privilege against self-incrimination.

Jim March, a Libertarian Party officer in Tucson, said he and John Brakey of the Pima County Democratic Party discovered that chief election technician Bryan Crane ran computer checks five days before the polling date to determine the vote tally based on more than 16,000 mail-in ballots.

Although it is not illegal to conduct such a check, it is unlawful to divulge the results because partisan activists could use pre-election tallies to decide on campaign finance and advertising strategies.

Something 'squirrelly'

March said testimony in the open-records case showed Pima County election staffers "were basically passing these results around like baseball scores."

"They were peeking into where votes were going," he added, "and there was something particularly squirrelly about the RTA election."

Brad Nelson, elections director for Pima County, said he does not believe there was any wrongdoing by employees. Crane did not respond to an interview offer made through Nelson. He has not been charged with any offense and continues overseeing Pima County's election technology.

Former Pima County employee Zbigniew Osmolski filed an affidavit in July alleging that he was in a Tucson lounge when Crane admitted that he had "fixed the RTA election on the instructions of his bosses" and was fearful of indictment.

That same month, Democratic Party attorney Bill Risner submitted a letter to Goddard asking that the criminal probe be reopened. Risner offered new evidence and complained of a cover-up during the first investigation, which was assisted by Pima County election officials.

Risner noted that, according to sworn courtroom testimony, Crane routinely took voting data home during elections and had his office computer connected to the GEMS system. He also claimed that Crane purchased a hacking device before the election, one with "no other purpose than to illegally alter the programming of precinct voting machines."

No county employee has been disciplined, Risner said, despite criminal and policy violations.

Goddard said he agreed to reinvestigate based on the "worrisome number of puzzling coincidences." To establish whether a crime took place, he added, the state must first learn whether the election outcome was bogus. That is why poll workers are hand-counting 105 boxes of ballots at a cost of over $12,000. The review is being done in Maricopa County, where Premier machines are not used, to avoid a conflict of interest.

Yet even the review, expected to end today, has been controversial. Critics questioned ballot security before the count and complained that Goddard's office limited their ability to observe the tabulation.

'Plenty annoyed'

"They're doing it in a way to make sure that the political parties don't know what's going on," Risner complained. "We're plenty annoyed with the secrecy."

The RTA has collected about $210 million since the sales-tax increase began three years ago.

If the recount shows that the measure should have failed, Goddard said, election results will not automatically be overturned. However, he said, such a finding could lead critics to seek court orders overturning the outcome.

But Nelson, the Pima County elections director, said he is convinced the original vote count was right. He said no new security has been added to the Premier system, "one of the best out there."

However, Nelson added, the county has instituted external safeguards to reduce the risk of tampering. The list includes a password system so no single employee can access the computer and 24-hour video surveillance of computers, beamed live on the Internet.

Risner's letter to Goddard portrays the more sinister image of election-fraud, adding, "Anything less than an honest count of the ballots is a crime that strikes at the heart of our democratic system."