Criminals are trolling the internet looking to take advantage of you and sometimes the schemes they come up with can be very convincing. And if you take the bait you could lose a lot of money.

When a West Vancouver woman got a cheque in the mail from someone wanting to buy her bike she had listed on Craigslist, she went straight to the bank with it.

Despite the fact the bike was only listed for $1,200, the buyer had sent Carrie Okines a cheque for $3,200.

“I didn’t want to be a pessimist and not trust this person,” said Okines.

In the emails, the buyer said they were working offshore and was sending extra money to hold the item and for shipping. The buyer requested she then transfer back the difference.

“This is an overpayment scam,” explained Const. Kevin Goodmurphy, with the West Vancouver police. “Usually the cheques appear to be legitimate cheques.”

In Okines’s case, the cheque had a real account number and was from a real business in Calgary.

“They’re really trying to rip us off and using our name and making us look bad to a variety of people across the country," said Brad Fincaryk, president of Nemalux, the company named on the fraudulent cheques. "I've gotten calls from Vancouver, couple in Alberta, some in Ontario and Quebec."

And police warn the culprits can be pushy.

“[They’ll push] to do the deal now. To put a deposit down. To quickly deposit that cheque and then again quickly forward that money to them before the bank catches this cheque to be fraudulent.”

Okines asked her bank to investigate.

“Anytime we’re finding a situation when someone is receiving a cheque or item and being asked to return the difference to someone, that’s a fraud alert for us,” said Chris Maze, RBC director of regional operations.

“[The bank] caught it right away,” said Fincaryk, “My count right now is about 20 cheques that I’m aware of that have been tried to get passed.”

Police now have Okines’s first cheque, but to try to entice her again to transfer money, the fraudster sent another.

“It was the exact same check simply a different cheque number," she explained.

“People do fall for it. I mean they are very crafty in what they do,” said Const. Goodmurphy.

So what happens if you do end up transferring the difference?

"When an item is fraudulent or counterfeit or altered that could take up to three months for the item to get returned," said Maze. And if it does come back as fraudulent the money would be reversed from your account, leaving you on the hook.

Okines bike still hasn’t sold, but she’s glad she trusted her instincts.

Remember if something doesn't seem right slow down and ask questions. Don't be pressured. Better yet deal with someone in person and with cash.

A lot of police departments like West Vancouver offer safe trading zones monitored by security cameras where you can meet potential buyers during regular business hours.