CONCORD, N.H. – Undercover officers tailed the three men as they went from store to store at Tanger Outlet Mall in Tilton in summer 2011, watching them load up on high-end merchandise and carry armloads of bags to a rented Dodge Durango with Pennsylvania plates.

Other officers lingered at the stores the men had left, calling the people whose names appeared on the checks the men had passed. One after another, they told police they didn’t have accounts at the banks shown on the checks bearing their names.

Minutes later, police arrested the trio, who have since agreed to plead guilty to being involved in a massive nationwide identity theft and check counterfeiting ring. Two of them had been sought by Walmart security officials for two years for cashing more than $370,000 worth of counterfeit payroll checks.

“Their method of operation was to be on the road,” Tilton Police Chief Robert Cormier said. “Sometimes they didn’t know which state they were in. They’d just follow the GPS to the next block of stores.”

Edgar Rose of Pittsburgh and Omar Patterson of Cleveland have both agreed to plead guilty to wire fraud. Quentin West of Pittsburgh agreed to plead guilty to wire fraud and aggravated identity theft. All three are scheduled to be sentenced next month in U.S. District Court in Concord.

Now, their plea agreements and other federal court documents in their cases reveal new details about the scope of the conspiracy, including what records they kept of others’ personal information and the dozens of fake IDs they’re accused of carrying.

When the men were apprehended on Aug. 23, 2011, the car they were driving contained records listing Social Security numbers, dates of birth, mother’s maiden names and other personal information of hundreds of people whose identities had been stolen, Cormier said. He said the trio also kept detailed records of which stolen identities each of them used and at which stores.

Walmart security officials say 270 people had their identities misused on checks the retail giant cashed, according to West’s plea agreement.

Federal investigators identify Rose, a graphic designer by trade, as the ringleader. He and West had been counterfeiting checks for about three years, Rose told investigators. Patterson had only recently joined them, he said.

West told investigators that Rose would give him half the proceeds of the counterfeit payroll checks they cashed. The checks were usually written for sums of less than $1,300. He said the companies on the payroll checks were fake but the identities on the checks were real and stolen. Investigators say Rose and West created fake photo IDs bearing their images to match the names on the checks.

According to the plea agreements, more than 50 fake IDs were found in the Durango along with dozens of counterfeit payroll checks.

Cormier said he suspects they got the victims’ information from one of the leading credit reporting agencies but does not know whether it was obtained by hackers or an accomplice within the company. The Secret Service is investigating, he said, and has linked the three to a national ring based in Georgia.

Their scheme unraveled when an off-duty loss prevention investigator from Kohl’s department stores who was on vacation in New Hampshire and shopping with his wife happened to be in line behind the men when a Brooks Brothers clerk challenged the identification being used. The investigator, Michael DeMeo, became suspicious and called Tilton police. He continued to monitor the men until police arrived.