County election officials across the metro area are scrutinizing dozens of voter registrations tied to commercial mail centers after a probe in Minneapolis revealed a loophole in the state's election system.

A new Star Tribune comparison of voter records and data from the U.S. Postal Service found that 95 voters were registered at the addresses of mail centers — such as UPS Stores — despite requirements that voters list their physical residence.

The findings show that illegal voter registration at mail centers extend beyond a Cedar-Riverside shopping center in Minneapolis, a previously unregistered center that became the target of a complaint when it was discovered that 141 would-be voters had registered there.

The Star Tribune's inquiry unearthed a batch of private mail centers scattered from St. Cloud to Duluth that were previously unknown to several county election officials, who said they are now canceling or challenging voter registrations at those locations.

The secretary of state's office only recently sent a complete list to county officials around the state.

People sometimes use private mailboxes to receive mail, particularly if they move frequently, and may list it on voter registrations separately from their residential address. One St. Cloud voter contacted by the Star Tribune said he was unaware he could not register a nearby UPS Store as his primary address.

"We are … in the process of notifying the people who are registered at those addresses that we are going to cancel unless they have some evidence to give us that they actually live at those addresses," Hennepin County election manager Ginny Gelms said.

The county actively sought out the list of mail centers from the Postal Service and has deactivated 31 registrations at three locations until voters provide that evidence. One of those locations is also in the Cedar-Riverside neighborhood.

Election officials have been paying closer attention to mail centers after an attorney for Rep. Phyllis Kahn, Brian Rice, discovered hundreds of registrations at the Cedar Mailbox Center in the basement of a Somali shopping center. But that mail center was not on the Postal Service list of registered mail centers, raising the possibility that other mail centers like it could still be flying under the radar.

Jeff Long, a postal inspector, said they have instructed postal carriers to be on the lookout for other unregistered businesses "operating under the guise of a commercial mail receiving agency."

Long said it was an "oversight" that the Cedar Mailbox Center was not registered.

The Cedar-Riverside example showed that most mailbox registrations are incidental, muting concerns of a voter fraud effort.

Forty-nine voters were registered there because they had submitted change- of-address forms, which also switched their voter registration address following a verification process. While post office boxes are easy to catch and flag as ineligible, mail centers look like a traditional address.

Alerting counties

The secretary of state's office recently provided counties across the state with a list of all registered commercial mail centers to help eliminate improper registrations. Postal Service data obtained by the Star Tribune showed 62 are scattered around the state.

"Only in recent weeks did we become aware that commercial mail centers are required to register with the post office, and that it would be possible to obtain a list that counties can use to help them identify and weed out such addresses," secretary of state's office spokesman Nathan Bowie said.

The office could not provide its total for the number of voters registered at those addresses by the Star Tribune's press time.

Bowie cautioned that even that number may not tell the whole story, however, since it is possible people could live in apartments above a mail center.

Andy Lokken, elections manager at Dakota County, said officials there were investigating four mail center addresses provided to the county by the Star Tribune — three of which are UPS Stores. Removing improper addresses from the precinct finder is an ongoing process, he said.

An additional 14 people were registered at a UPS Store in St. Cloud. Stearns County elections director Dave Walz said they challenged all of the voters at that address after a Star Tribune inquiry, which he said will require those voters to show a form of ID at the polls.

His staff has been culling phone books and the Internet for other mail center examples but haven't found any so far.

"The trick is becoming aware of the places," Lokken said. "They don't send us a letter when they open up a UPS Store."

Staff writer Glenn Howatt contributed to this report.

Eric Roper • 612-673-1732

Twitter: @StribRoper