If you drove past it, you might not have even known the building sitting off a Douglas County road was an emissions testing center.

And though the sign outside may have said otherwise, this testing center wasn't open to the public, according to the state Department of Natural Resources.

Instead, surveillance cameras showed the same vehicle being tested repeatedly as part of a scam to provide passing tests to vehicles that otherwise might not pass, Todd Binion, criminal investigator with the DNR's Environmental Protection Division., told the AJC Wednesday.

The fraudulent testing center was only in operation last fall for about a week before the man running it, Tavaris Despinosse, was arrested, Binion said. Investigators believe Despinosse was the ring leader of the operation, which involved the alleged criminals pocketing $150 to produce a fake passing test. He was arrested Dec. 19 and later released after posting $50,000 bond, according to Douglas County jail records.

On Tuesday, nine others involved in the alleged crime ring were arrested in an operation involving several agencies, including the Douglas County Sheriff's Office and the U.S. Marshals, Binion said. One suspect remains on the run.

During their court appearances Wednesday, five of the suspects were denied bond, three were given bond amounts of $40,000 and bond for the ninth suspect was set at $10,000. Additional arrests are possible, Binion said.

A similar case in Fulton County led investigators to the Douglas County case, one of the biggest busts of its kind, Binion said.

State law allows testing sites to charge anywhere from $10 to $25 for emissions tests, but those involved in producing the passing tests charged $150, Binion said.

Out of the millions of test conducted each year, only a small percentage are fraudulent, Binion said.

"Unfortunately, a lot of the people have been told misinformation," Binion said. "They believe it's going to cost several hundred dollars to fix [their car]."

But often, vehicles can be brought up the state's emission standards without breaking the bank, he said.

Also, consumers should make sure they're getting a legitimate test.

"Make sure that when you take your vehicle, you watch them test your vehicle," Binion said. "By state law, you have to be able to watch the test."