Dr. Balaji Krishnan was driving home from work at the University of Minnesota when he got the call.

The man on the other end of the line, who identified himself as a “federal officer,” rattled off Krishnan’s name, address, cellphone number — and then said there was a warrant out for his arrest. The caller said police officers would arrive at Krishnan’s home shortly. To avoid that, he could buy a prepaid credit card and read the number over the phone, in payment of $1,183 in alleged back taxes.

Personal, targeted phone scams are on the rise, hitting people around the world and sometimes convincing them to give up thousands of dollars. Krishnan, a 33-year-old cardiology fellow at the U and St. Paul resident, realized he was being conned and reported the incident to St. Paul police.

But the amount of information the caller had about him — not to mention the threat of arrest — caught him off-guard.

“You think you’re pretty savvy, but this was really good,” Krishnan said. “I tell you, it was really good.”

The Minnesota attorney general’s office recently issued a consumer alert warning about tax-related fraud, including “intimidation scams” like the one Krishnan experienced.

In March, the U.S. Treasury Inspector General for Tax Administration issued a similar warning, saying in a news release that it was aware of thousands of victims who together paid more than $1 million to scammers posing as IRS agents.

“This is the largest scam of its kind that we have ever seen,” Treasury Inspector General for Tax Administration J. Russell George said in the release.

According to the release, scammers are often armed with fake IRS badge numbers, spoofed numbers giving the appearance of a call from the IRS or another official agency and personal details about the victim.

Massoud Amin, a U professor and director of the Technological Leadership Institute, said this kind of targeting emerged last year and has grown steadily. Calls aren’t always from faux IRS agents; scammers pose as debt collectors, representatives of charitable organizations or even relatives. The rise in these scams isn’t surprising, Amin said, because so many people share personal information online that’s easy for scammers to find or buy.

That access to personal information “changes the game,” he said, because it allows scammers to more easily convince victims that a call is legitimate.

Caught off-guard

That was the case for Krishnan. “I’m naive,” he said. “I think, ‘Who ... would know these numbers but the government?’”

What tipped him off, he said, was the caller’s insistence that he use cash to buy the prepaid credit card. He told the caller his phone was running low on battery and hung up, then headed to the nearest police station.

St. Paul police spokesman Howie Padilla said though the attributes of these scams differ — a recent one asked people to donate to a public-safety fund, for example — there’s one thing they often share: “They all ask for the same thing: ‘Put money on these cards, put money on these cards,’ ” he said.

Amin said people who suspect they’re receiving a scam phone call should get as much information as possible from the caller, including their phone number, and try to verify it. If the information turns out not to be legitimate, he said, the recipient should contact local police and FBI. The Treasury agency asks that victims of IRS impersonation scams report incidents directly.

Krishnan’s incident ended at the police station, when he got another call from the same number. He handed his phone to a police officer, and the caller started asking for her badge number. When the officer told him he’d be arrested if he continued the impersonation, the line went dead.