NASHVILLE, Tenn. -- A former employee of Metro security contractor Wackenhut said the company has falsely billed Metro for services.

Video: Ex-Security Employee Says Company Falsely Billed Metro

Wackenhut is the security contractor Metro Nashville hired to be in charge of some of its buildings. It was under a subcontractor of Wackenhut’s, Specialized Security Services in Wilson County, that laptops loaded with sensitive voter information disappeared.

Accusations were also made by former employees of Wackenhut that the company billed Metro for services that weren’t performed.

Tax dollars pay for Wackenhut guards to watch buildings in Metro from the Election Commission to juvenile court, but a former employee said Metro taxpayers were billed for Wackenhut to guard a Trinity Lane motel.

The man used to be a supervisor for Wackenhut, and he said he was curious about an invoice the company sent to Metro. He asked that his identity remain hidden.

He said Wackenhut billed Metro for a guard to work the third shift at Nashville’s temporary courthouse on near Metrocenter Boulevard.

"When I looked at it, I knew we didn't have a third shift at Metrocenter,” he said.

The former employee said it was a “ghost shift” billed to Metro and that the guard really worked the hours at a motel which until recently was a Motel 6.

"He was working another account, but it was billed to Metro,” the man said.

Three other current or former security employees verify his story, reported Channel 4's Nancy Amons.

The former employees said they questioned Wackenhut's bosses, who issued Metro a refund.

"It's not right. We're paying for services we're not getting and it's not right,” the former employee said.

Wackenhut's corporate spokesman in Florida said "a minor error" was made and that the “discrepancy was discovered by us and corrected.”

But former employees said it happened more than once and that they believe it was part of a wider pattern of Wackenhut billing Metro for security guards who weren't really there. The findings are being investigated by Metro's top finance officials.

"This is something we need to jump on immediately,” said Finance Director Rich Riebling.

On Tuesday, Metro officials said they believe Wackenhut overcharged taxpayers for three months in the billing for 12-hour Saturday shifts that were unmanned.

In May, WTVJ in Miami interviewed security personnel who formerly worked for Wackenhut, and those people told the station it was common for Wackenhut to bill for guards who weren't really at their posts.

Federal authorities are also investigating Wackenhut's corporate office.

Wackenhut released a statement on Wednesday about the billing discrepancies Metro found. The company said it relied on its subcontractor to see that all the posts were staffed and if they weren't, Wackenhut said it will pay Metro back.

Wackenhut Security’s CEO left the company officially on Wednesday.

The company is also under fire in other states facing claims of sleeping guards at nuclear plants and ghost workers on the payroll in south Florida.