CHICAGO – Out of a small generator-powered shack on the city’s north side, a man periodically emerges to hand COVID-19 testing kits to people waiting in cars or shivering in the parking lot.

As he opens the door, piles of plastic bags, apparently grouped by test type, can be seen in crates on the ground. He encourages test-takers to scan a QR code with their phones, fill out an online form with identifying information and write a digitally-generated string of numbers on a paper sheet inside the plastic test kit bag.

Test-takers swab their noses and hand over the bags, free of charge. Some say they receive results many days later than promised – if they hear back at all.

As Americans nationwide continue to scramble for access to quick, reliable COVID-19 tests amid a national shortage, state and local authorities are warning residents to be on the lookout for fraudulent pop-up sites trying to scam people out of money and personal information. Some regretful test-takers spoke to USA TODAY about a particular string of testing centers: the so-called “Center for COVID Control.”

The Center for COVID Control operates more than 300 locations across at least 29 states, according to the company’s website. The locations pop up on Google maps searches with minimal information about the testing site beyond location and hours. The website claims the company is “partnered with a CDC approved & licensed laboratory” but does not specify which lab.

A Twitter account linking to the website has no followers and was created in March of last year. “We also offer rapid test for $100,” the Twitter bio says.

An Instagram account linked from the website goes by the handle “freecovidtest” and first began posting in December, 2020. Multiple users have commented on posts to the account, calling the testing site a “scam” and “fake.”

Minneapolis resident Christina Weber, 31, a full-time server, said she Googled “free COVID testing near me” and saw a Center for COVID Control site pop up on Google Maps. When she drove down to the site to get a test at the end of December, the site was located a block away from the address listed online.

“It was just a pop-up. There was one man running the whole thing, and he was in his scrubs,” Weber said Friday. “The area where you waited was the same area where people were testing, and the chairs weren’t spaced out. And some of the guests weren’t wearing masks.”

Weber said a man stormed into the site while she was there and started yelling that he hadn’t gotten his results. She said she was instructed to self-administer a test and drop the plastic bag into a tray overflowing with about 50 other bags. She left the site feeling uneasy and decided to get a second test at another location.

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After she didn’t hear back for several days, Weber said she began posting complaints on the site’s social media pages, which she believes prompted the testing site to email her results, which were sent from “results@dcltesting.com.” While the result from the Center for COVID Control was negative, the result she received from the second test that day was positive, Weber said.

“I felt like they just sent the negative results,” Weber said. “I got upset and worried thinking they’re gonna kill somebody if they keep sending out these false negatives.”

Weber said she reported the testing site to local officials and was later contacted by an investigator for the Minnesota Attorney General’s Office, who informed her that she was not the first to report issues with the testing site. The office did not immediately respond to USA TODAY request for comment.

USA TODAY attempted to contact the Center for COVID Control via the main phone line listed on its website over the course of three days and was given over an hour wait each time. USA TODAY also called an additional phone line listed for the company in public records but was unable to leave a voicemail.

The company’s principal and mailing address is the same Rolling Meadows address, a one-story commercial office building about 15 miles northwest of O’Hare International Airport.

The manager of the Center for COVID Control is Aleya Siyaj of Rolling Meadows, Illinois, according to the Florida and Illinois Secretaries of State. In Florida, the company’s registered agent is Fawzia Safdari of Davie, Florida. Siyaj and Safdari did not respond to USA TODAY voicemails or email request for comment.

Scores of Center for COVID Control locations are in the Chicago area, according to the website. Dozens more are reportedly in Florida and Texas. The company registered in Illinois, Florida and Washington at the end of 2021, according to records from the respective Secretaries of State.

Florida’s attorney general issued a statement Thursday warning about new and re-emerging COVID-19 test scams. The statement, which did not name the Center for COVID Control, cited “recent reports of suspicious COVID-19 testing sites popping up in Illinois” that “appear legitimate but are designed to steal personal information from unsuspecting test seekers.”

Asked about the company’s testing sites in Florida, Florida’s Agency for Health Care Administration did not immediately respond to request for comment. The Florida Department of Health, speaking generally, said “Floridians are urged to be on the lookout for fraudulent COVID-19 products and practices, especially as it pertains to testing.”

Washington State has received two complaints about the company, according to the Washington State Attorney General’s Office. People in Chicago, Houston and Rochester, New York, told USA TODAY they experienced issues with Center for COVID Control testing sites.

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In a press conference Monday, Dr. Ngozi Ezike, director of the Illinois Department of Public Health, urged caution for residents getting tested at pop-up sites. The Illinois Department of Health maintains a list of bonafide community testing sites, Ezike said. The Center for COVID Control is not on that list.

“There unfortunately are those who are taking advantage of these crazy times to try to scam people,” she said.

Illinois Gov. J.B. Pritzker said some testing sites are returning test results after long delays or not at all. Pritzker said his office relayed the issue to the Illinois attorney general’s office for further investigation. Asked if the Center for COVID Control was part of that investigation, the Illinois attorney general’s office did not immediately respond.

At least two people complained about the Center for COVID Control testing sites to the Oregon Department of Justice, spokesperson Kristina Edmunson said. The complaints reviewed by USA TODAY ring similar to Weber’s account.

“I have not received results and have grown concerned that I fell victim to a scam,” one person said. “The test site also felt very fishy, when I arrived it was just a tent with a couple people standing around a convenience store parking lot, and I was given the test kit to perform on myself in my car.”

Another person alleged the site billed their insurance for a test, which was labeled as having expired in June of 2021.

“This is very concerning to me as a pandemic-conscientious citizen. I got tested because I had respiratory symptoms that could be Covid or could be an unusual burst of allergies,” the complaint said. “The expired rapid test came up Negative, but was I REALLY definitely Negative?”

The Oregon Department of Justice does not have an open investigation, Edmunson said.

The Texas Department of State Health Services had “not heard” of the company, spokesperson Douglas Loveday said.

In Brazos County, Texas, a local police officer noticed two testing sites operated by the Center for COVID Control pop up last week, Brazos County Health District spokesperson Mary Parrish told USA TODAY.

“They do not have any agreement with the Texas Department of State Health Services, and they have not been reporting their cases to us,” Parrish said. “The reason that’s concerning is because not only do we not get cases reported to us, but it goes against the governor’s executive order.”

Parrish said county health district officials have struggled to contact representatives of the testing sites.

“One of our managers spent over three and a half hours yesterday on hold trying to speak with someone from COVID Control. Even then, he was kind of given the run-around,” Parrish said.

The district official contacted the Center for COVID Control through the main phone line and was transferred to a manager identified only as “Ash,” Parrish said.

Parrish said the manager informed the district the company was “working with their IT department to put plans in place to get on board with the state and secure data safely.”

As of Friday afternoon, the company had not made testing results available to the health district, Parrish said.

“The next steps for us really is just going to be keeping a watchful eye on them. We don’t have the authority to close them down. Really all we can do is watch and wait see what happens. This is not an approach we like to take in the field of public health,” Parrish said.

Asked about the company, the FDA said: “The FDA regulates and reviews COVID-19 diagnostics. Companies providing testing services are not within the FDA’s purview.”

A test given to a USA TODAY reporter at a Chicago locationSunday – in red transparent vial – was taped with the label “SNT Biotech.” According to the company’s website, SNT Biotech is “a DBA of Saris and Things, Inc.” Saris and Things is a Plainfield, Illinois, company that sells saris, lehengas, anarkalis and sherwanis, according to the website.

Shital Daftari, founder and owner of Saris and Things and SNT Biotech, said her company sources swabs, tubes and masks and other supplies from the U.S., Finland and elsewhere and sells to labs and testing sites in the Chicago area. She said the Center for COVID Control “bought a few supplies from us in the past.” Daftari said her company is not a lab and does not process the tests.

Have you experienced issues with the Center for COVID Control? Contact reporter Grace Hauck at ghauck@usatoday.com.