A Montreal woman is sounding the alarm after she was robbed by an apparent Good Samaritan who helped her with a flat tire.

The feigned good deed appears to have been part of a larger criminal scheme police say they have seen before. They're urging others to be vigilant.

Caroline, who doesn't want her last name used, said she was waiting at the lights at the corner of Atwater Ave. and Rene-Levesque Blvd. opn Dec. 31 when someone knocked on the window of her car to let her know she had a flat tire.

Never having changed a flat before, she said didn't know what to do, and pulled her car over to have a closer look.

“I went down and saw the tire was flat, flat on the ground. It was like it wasn't even halfway to go to the gas station,” she said.

To her relief, a Good Samaritan came by and offered to help.

“I thought, maybe he can change it and I'll pay him and I'll leave,” she said.

Caroline said he had her open the trunk and pull out all the equipment to change the tire, then told her a piece of equipment was missing and abruptly left.

When she got in the car to call a mechanic, she realized there was something missing: her purse.

“It was all my life. $3000 worth of cash, all my ID cards, all my business cards. My other Blackberry phone. Everything related to my business,” she said.

She called police and had to be treated for shock.

Her mechanic Karim Abdul later came to the scene to help, and upon examining the tire, said there was clear evidence the tires were slashed by a knife.

“This is not an accident, by cutting like this it takes a tire a minute or even 30 second for a tire to go flat,” he said.

Police are now investigating.

“We are also trying to see if there are other events happening in that area. We know that a similar event did occur in the past but it is the same group of people? That's still to be determined,” said Montreal police spokesperson Raphael Bergeron.

Caroline is having all her locks changed, and said insurance won't cover the stolen cash.

Having all her personal information stolen has also robbed her of sleep and more.

“At this point I'm doubting everybody,” she said.