ATLANTA -- The FBI is looking for three serial bank robbers that have hit a dozen metro Atlanta banks since August.

Investigators are most concerned with a pair of robbers who's hit six area banks in a month, according to the FBI's Steve Emmett.

"On the six occasions they've robbed, they've gotten money at each of these robberies, so it is totaling up to a pretty significant loss amount," said Emmett.

The first robbery occurred at a Wachovia bank in Riverdale on October 13, followed by a SunTrust bank in Forest Park, a Chase bank in Morrow, another Suntrust bank in Forest Park, and two RBC banks - one in Morrow, one in Jonesboro, on the same day in November.

"One of the robbers has a gold wedding band ring on his right index finger. That's clearly displayed in one of the photographs," said Emmett.

Emmett said while they're suspected in those six, they could be responsible for a lot more.

The other serial bank robber, who works alone, has also hit six banks since August. The robber hit Wachovia banks in Stockbridge, Fairburn, Conyers, Riverdale, and Tucker. He also hit a Bank of America in Stockbridge.

He's described as a black male, mid 30s, possible tattoo on his right forearm and on his neck, and a gold cap on a bottom tooth. He may be driving a teal green Nissan Sentra with Georgia tags or a white four-door Kia/Nissan with drive out plates.

Anyone with information is asked to contact the Atlanta office of the FBI at 404-679-9000.