A Calgary senior lost $7,000 in a scam when someone claiming to be a bank manager phoned to enlist her help in trapping a thief.

The victim, 90, received a phone call last Thursday morning from a man who said he worked at the bank branch that she dealt with. He claimed he needed her money to help catch a thief who worked at that branch.

The man pushed her to withdraw cash and to meet outside a supermarket in Westhills, not far from the bank.

After the victim handed over the money and returned home, the man phoned again and said he needed more cash to trap the thief. The woman complied again and gave the fraudster more cash.

"This person gives whoever he calls a very limited time to respond. We're sure that's part of his plan so there is no time to contact anybody else or get advice," Det. Shawn Kangarloo told CBC News on Monday.

It was only after handing over about $7,000 that the woman called members of her family, who reported the incident to police.

Scam usually targets seniors

Kangarloo said this type of scam, typically targeting seniors, is very common and the con man could be travelling across Canada.

"We don't believe he's going to hit Calgary in the next short while and most likely moved on to a different city," he said, adding that suspects in these types of scams are usually well-dressed, middle-aged men.

Kangarloo said investigators know how the suspect uncovered the victim's bank branch but did not divulge the details.

"What we don't want to do is generate copycats," he said.

Police warned the public to never give bank details over the phone, and to call authorities immediately about suspicious activity.

With files from Andree Lau