With ballot counting finally wrapped up Monday, Pima County officials are beginning to investigate why more than 27,000 voters received provisional ballots on Election Day.

The county's adviser on technical issues is already cautioning that it could be difficult to figure out exactly what glitches caused the problem.

A forensic audit of the voter database maintained by the Recorder's Office could provide answers, but it has been changed since Election Day to account for voter deaths, said John Moffatt, director of the county's Office of Strategic Technology Planning.

"It's very hard to do forensic work on live databases," he said. "They need to freeze that file. They need to create a file for the election that is static."

Instead, most days, an employee in the Recorder's Office gets the tedious task of cutting obituaries and death listings out of local publications and checking them against voter rolls.

Arizona death certificates are not public records, unavailable even to Recorder's Offices updating voter rolls, so the process of updating the lists is something of a jigsaw puzzle.

When employees know a voter who dies, managers take them off the rolls. Some families send a copy of a loved one's death certificate to the office, and sometimes the office finds out about a death through its property recording side when a family begins to divide a loved one's land holdings.

The one automatic part of the system is triggered when a voter registers in another Arizona county. Then, he or she is immediately dropped from Pima County's list, said Chris Roads, deputy county recorder and registrar of voters.

The process is continual, but it was slowed as employees waded through verifying the tens of thousands of provisional ballots and early ballots turned in at the polls, said Pima County Recorder F. Ann Rodriguez, who was re-elected this election.

And there is a saved record of the voter rosters - lists sent to the precincts that together comprise something like a snapshot of the database at the time. "We can go back and check those," she said.

This election, there were problems with the lists reviewed by poll workers, and an unusually large number of voters received provisional ballots that were counted after Election Day, and only after extra verification. Some voter names seemed to be missing. Others weren't where they were expected to be.

Confusion was already high on Election Day for other reasons.

Many voters went to the wrong polling location, often one they had gone to for years.

But polling places changed for many voters because of redistricting, which takes place every 10 years, and the consolidation of polling places since, with about 68 percent of voters casting their ballots early, fewer polling places were needed than in the past.

Some glitches have already been identified, but their root cause is still unknown.

So far, what is known is that voters who registered to vote on the last day they were eligible were added to the precinct lists, but for some reason, their names were not alphabetized with the rest of the list. It affected some precincts, but not others, and only names beginning with certain letters, Rodriguez said.

The Elections Department also caught an error related to how ballots were striped to indicate to poll workers in split precincts - such as those partially in the city and partly out - which ballot type to give each voter, Moffatt said. About 60 of 288 precincts received new materials on Election Day, he said.

Although Moffatt describes Rodriguez and her staff as "meticulous" and the voter list errors as "an anomaly," he has begun to develop recommendations for the next election cycle.

"It shouldn't be up to the Elections Department or the poll workers to do quality control" for the Recorder's Office, he said.

On the upside, Moffatt said elections workers got an emergency phone system up in 15 minutes once they realized there were problems with the voter lists and poll workers weren't able to reach the Recorder's Office because of jammed lines.

A meeting is scheduled for mid-December to decide whether the office needs more phone lines, he said.

On StarNet: For results of the 2012 election, go to azstarnet.com/elections.

Contact reporter Carli Brosseau at cbrosseau@azstarnet.com or 573-4197. On Twitter @carlibrosseau.