When Andre Cherkasov reported suspicious fraud activity while working at the Richfield Best Buy over the holidays, he didn't know he might be coming to the rescue of scores of victims of identity theft across the Twin Cities.

Cherkasov was wary when a woman named Linea Palmisano opened a credit card account.

"Just the way she behaved, I kind of knew she was on some kind of a substance," Cherkasov said in a recent interview.

After the woman was approved, she pulled down her mask, and Cherkasov immediately saw her face didn't match the photo on her paperwork. He shared his concerns with Richfield police officer Amanda Johnson, who was working at the store and looked up Palmisano online. Not a match there, either.

Before long, the real Linea Palmisano — a Minneapolis City Council member — received a message asking if she had just opened a credit line at Best Buy. And Johnson soon arrested the fake Palmisano, who turned out to be Emily Gerst, 33, of Minneapolis.

The arrest opened the door to an investigation into a six-month crime spree during which Gerst and Thomas Stoyka, 36, of Minneapolis, allegedly stole the identities of 158 people in the metro area. Each is charged with one count of felony identity theft.

Using big-box store credit cards issued in Palmisano's name, the couple managed to steal $12,000 in just 10 days. Palmisano said she didn't know how long they would've kept at it if Cherkasov hadn't stepped in.

"No one … stood up for me or any of these other victims that I know about until Andre did," Palmisano said. "And then officer Amanda Johnson really honed in and connected all of these dots together."

Gerst is scheduled to appear in court Sept. 6, while Stoyka's whereabouts are unknown; a warrant has been issued nationwide for his arrest. The charges recently filed in Hennepin County District Court allege a loss of more than $35,000. Court records show that many of the items they purchased with fraudulent credit cards were pawned.

According to the charging documents, Gerst and Stoyka operated out of a storage unit on Hiawatha Avenue in Minneapolis. Police found there a wig, printer, laptop, blank checks, lock picks, keys, a state Driver and Vehicle Services stamper, a flexible pipe camera and a grabber tool to steal mail — all used to forge paperwork, steal identities and open bank and credit cards through stores and online apps such as Apple Pay.

Shortly after Gerst opened the credit account at Best Buy on Dec. 20, Johnson watched as she, Stoyka and an unidentified man went to the counter to buy more than $2,000 worth of items. According to court records, Stoyka and the other man went outside and got into what turned out to be a stolen SUV. The unidentified man went back into the store to join Gerst while other cops pulled into the parking lot.

Stoyka fled, driving "so recklessly that they called off the pursuit." Gerst, who refused to identify herself, had in her possession a credit card belonging to another victim and the printed driver's license for Palmisano.

Throughout the subsequent investigation, Johnson discovered just how elaborate and widespread the couple's operation was. After sifting through the stolen mail and forged paperwork in the storage unit, the officer counted 158 identity-theft victims and was able to contact 124 of them to confirm their information was stolen.

According to court documents, Gerst and Stoyka's cellphones and tablets contained a bevy of how-tos and internet searches on committing fraud. Stoyka's phone had a video of him holding hundreds of dollars, and an iPad had photos of personal checks. Gerst's phone, according to court documents, "contained personal identifying information belonging to numerous other identity theft victims."

Gerst and Stoyka also face felony identity theft charges connected to a May burglary in Edina. Surveillance video captured the couple entering an underground garage on York Avenue in a stolen Subaru Forester. Police later searched the vehicle, abandoned in Minneapolis, and found stolen mail, ledgers, a box of washed checks and a bag of unused syringes. Along with stolen personal identification for more than 100 people, the couple had left information on themselves — including a court reminder notice for Gerst.

Edina police detective Jason Behr said Tuesday that he believes most of the 100 victims are in addition to those identified in the Richfield investigation, making it a "fairly significant case."

Palmisano was in Chicago for the holidays, sitting around the dining room table with her family when she received a dispatch call asking if she had just opened a line of credit at Best Buy in Richfield. Though she never had her wallet or IDs stolen, Palmisano said Gerst and Stoyka somehow got her Social Security number and used it to open credit card accounts.

"Prior to this, I've never really been mistaken for anyone else," she said. "And my own blind spot was that I was feeling pretty fine and safe."

Cherkasov said that when he reported his suspicions to Johnson, he didn't know that Palmisano was a Minneapolis City Council member. All that mattered, he said, was that someone was being harmed.

"I believe in karma," he said. "Somebody does something good for you, then you'll get something good in return in the future. I just hope that everybody's just like that — you know, make the world a better place."

Palmisano said she considers herself lucky. Despite a freeze on her credit, she said she didn't have to take out a new credit card, refinance her home or get a new car. While the process consumed hundreds of hours and cost her thousands of dollars, she said, the greatest loss was her own sense of security.

But she said her faith in society was slightly restored by Cherkasov's vigilance. In a postcard to him, she wrote that he was "a constant angel in my story of identity theft. And I will never forget it. Sincerely, Linea Palmisano (the only real one so far as I know.)"