CHICAGO (CBS) – Beware of the midnight caller warning you of trouble with your bank. It may very well be a call from thieves, targeting your credit cards and cash. CBS 2’s Mike Parker reports on a vicious scam targeting Chicago seniors.

It was almost midnight when Judy Sher was awakened by a caller. Sher says the woman on the line said she was with “the state of Illinois fraud division.”

The woman told Sher that an investigation was underway into North Bank, where Sher has an account; that her ATM and credit card had been deactivated and that a state “investigator” would be coming to her Gold Coast apartment to pick them up, along with her “PIN”, or personal identification numbers.

Although she was suspicious, she met the man in the dark outside her building.

“I gave him the credit cards and I can’t believe how gullible I was, how stupid,” Sher said. “I said to him, where’s your ID?”

And the man told her, “I don’t carry ID because I’m undercover.”

“While I was sleeping soundly in my bed, they were out having a shopping spree,” said Sher.

The crooks usually target residents of upscale high-rises. In fact, there was a second victim days later in Sher’s building. And there was yet another in a building just down the block on Bellevue Place.

Customers of several banks have been hit, including Chase Bank and North Bank.

North Bank’s president, Mayo Walcott, said, “It’s very troubling because the prey that they’re going after are the elderly, those that are the most vulnerable.”

Asked how she feels about the thieves, Judy Sher said, “They should all rot in hell. I don’t have any mercy for people who take advantage of anybody, whether you’re middle-aged, old, young.”

Sher says the criminals cleaned out $2,000 in cash from her ATM account, and that she hasn’t begun to total the illegal credit card charges.

Chicago Police have issued a bulletin to high-rises in the city, warning residents to be on alert.