The scammers were pros: They had the St. Paul restaurant's utility account number and the amount of its last utility bill when they called last spring and threatened to cut the power for lack of payment.

And for a second, restaurateur Lenny Russo hesitated. After all, he had a roomful of dinner reservations on the line.

"They catch you in the middle of the day when you have guests coming," said Russo, owner of Heartland Restaurant & Farm Direct Market.

Russo spoke out Tuesday to help launch a statewide "Slam the Scam" awareness campaign backed by 13 Minnesota utilities.

The campaign aims to combat a surge of swindles targeting utility customers, particularly small businesses with hefty power bills. Russo's experience is typical, the utilities say. Scam artists posing as utility employees call or e-mail to con people into paying, with some crooks even showing up at the door impersonating debt collectors.

Customer complaints are soaring. Xcel Energy alone has logged about 1,200 complaints of such scams this year, on pace to triple last year's total, and costing its customers $60,000.

"They're stealing our names in order to steal money from our customers," said Xcel regional vice president Laura McCarten.

McCarten, flanked by other utility executives gathered at Xcel's Minneapolis headquarters Tuesday, urged people to hang up and report scams to their utility and local law enforcement. Red flags include: aggressive behavior such as immediate demands for payment; attempts to limit the form of payment, such as requiring them to use a prepaid debit card; lack of a photo ID; and efforts to strike a deal to pay a portion of a bill.

Customers should know that utilities contact Minnesotans by mail about past due bills and potential service disconnections, they said. They will not send an e-mail with a bill and a link to make the payment. If customers are contacted by someone threatening to shut off their power, they should end the conversation.

Scammers know how to make their call show up on caller ID as a local call, so customers cannot trust that.

Dan Hendrickson, spokesman for the Better Business Bureau in St. Paul, said utility scams have been more prevalent since the recession with people operating on tighter budgets.

"When scammers see uncertainty, they go after it," Hendrickson said.

Hendrickson said it's rare for authorities to catch utility scammers, because prepaid cards and spoofed phone numbers are difficult to trace.

Russo said he didn't fall for the ruse, in part because he had a record of his electric bills in front of him. The kicker, he said, was when the con artist asked him to go to the pharmacy and get a prepaid card to settle the bill. "Good record-keeping is really your best protection," he said.

Jennifer Bjorhus • 612-673-4683