RALEIGH, N.C. — From the fraud investigation at the Wake County School System's transportation office to embezzling from private companies, white-collar crime is on the rise, according to the FBI.

According to the Association of Certified Fraud Examiners, the average business loses 6 percent of its annual revenue to fraud.

Since February, there have been at least eight different cases in the Triangle, including one involving employees of the Wake County School System Transportation Department and an automotive supply store.

FBI agent Andy Thomure says that loyalty could explain the multimillion-dollar fraud investigation involving the school system and one of its suppliers, Barnes Motor & Parts.

"It's common to find an employee who is loyal over the years," Thomure said. "They see a flaw, they never report it. Eventually they take advantage of the flaw themselves."

The attorney for Barnes Motor & Parts said former managers were able to maneuver the system because the system of checks and balances was simply out of date.

Thomure says identifying fraud is one hurdle and proving it is another.

"Any financial crime investigation is complicated in nature," Thomure said. "An investigator has to go through volumes to find the one nugget they need to prove their case."

And he says identifying one case does not prevent another, because fraud is often one part crime, one part betrayal.

The FBI said one factor contributing to the growth of white-collar crime is population growth.