Thou shall not steal is a commandment more employees are choosing to ignore, local police say.

The crimes can mean the theft of goods valued at a few dollars , such as a Lake Station gas station security guard charged with stealing a box of doughnuts. Or it can mean thefts amounting to thousands of dollars, such as a LaPorte man who scammed $100,000 from a Valparaiso roofing business where he worked.

And thefts hardly are limited to food and money.

Employees in recent months have been accused of pocketing pain-killers from a CVS Pharmacy in Hobart and taking home diamond rings from Jared Jewelry at Westfield Southlake mall.

"Employees are the biggest thieves," said veteran Hobart police Detective David Grissom. "They know where the money is and how to get around the system.

Last week, Grissom completed a case in which a 46-year-old Hobart woman was charged through Lake County with stealing $1,500 in cash from Cash In A Flash stores in both Hobart and Highland. The woman was fired from both businesses, but kept keys and knew the alarm systems. he said.

Grissom said one of the more common employee scams he is witnessing at retail stores is a clerk opening up a new credit card account for a customer then charging to that account.

"You almost have to check on your accounts on a daily basis," he advises.

Calumet City Patrolman Marco Glumac said police in his city also witness their share of employee theft at retail stores given that it has River Oaks Center.

But he recalls one of the more unusual cases of employee theft involved a 23-year-old Harris Bank employee who was arrested after helping two other friends steal more than $100,000.

The Calumet City woman -- who also was charged with putting $16,000 from her bank drawer in her own pocket -- was spotted on security camera footage unlocking a usually locked door for accomplices, Glumac said.

New technology has helped police and employers, but it cannot do everything.

"The cameras are there to survey employees and customers. There's plenty of ways to defraud," he said.

He recalls a Sears employee who handed out 26 televisions to friends through the delivery department; he wasn't caught for months. The man was clever enough to make a false paper trail.

And checking on the backgrounds of employees who might have criminal backgrounds is getting harder for police and in turn employers, at least in Illinois, said Lansing Police Chief Dan McDevitt. Changes in state law have sealed some types of criminal history records, he said.

Employee theft is not uncommon in Valparaiso, which has its own share of retails shops and chain stores, said Valparaiso police Sgt. Michael Grennes.

"It's not something new," he said. "There's usually a good paper trail to follow that leads back to the employee."