NOVI, Mich. -

Metro Detroit malls and stores are starting to get more traffic as consumers are stocking up for the holiday season.

Crooks already are making their move. They are watching, waiting and stalking shoppers.

Police sources in Troy, Birmingham, West Bloomfield, Canton Township and Novi say they have heard from shoppers who have been ripped off after they left the mall or store. Thieves are watching shoppers and waiting for them to leave the store. They follow the shoppers home. Once the victim is inside the home with the bags still in the car the thieves move in, taking the the newly-purchased items.

"They come by your car, they give it the eye," said retired police detective Tom Berry. "They are looking through front windshields. They are looking through the side windows."

Berry said the single-most important thing a shopper can do is empty their vehicle right when they get home. Nothing should be left inside.

"Take the time to take the stuff out of your car. Get it in the house and then go do what you have to do," he said. "Don't leave the stuff in the car. Don't make it easy for the thieves to take the stuff."

Local 4 spoke with shoppers Tuesday who said they are always on alert.

"I get the baby in the house first, lock the car. Go back down for the other tings and hope that people are kind and not being mean by nature, I guess," said Jennifer Kennedy.

Security will be beefed up at many malls during the holiday shopping period. However, once a shopper leaves the mall they are on their own.