(CNN) -- He has been captured by bank surveillance cameras in four states, sneering and holding a pistol sideways during heists.
The FBI is searching for this suspect, who they say has robbed at least 10 banks in the South.
Now authorities hope to catch the serial bank robber by plastering his image on electronic billboards throughout the South.
The FBI is searching for the suspect, who they say has robbed at least 10 banks in Kentucky, North Carolina, South Carolina and Tennessee.
The brazen bandit has been captured in surveillance footage sporting the same close-cropped hairstyle and goatee in many of the holdups. He does not seem to make any effort to cover his face and sometimes is seen aiming a handgun sideways, showing his tattoos on both forearms as he gestures at bank employees.
"It is uncommon to come in to a bank and show his face like he does," said FBI agent Kevin Keithley. Watch how the FBI hunts bank robbers »
The FBI has tracked the bank robber's path on a map that crisscrosses the southern United States.
The billboards that went up Monday roughly follow the path that the bank robber took, the FBI said. The billboards are in Alabama, Kentucky, Georgia, North Carolina, South Carolina, Tennessee, Virginia and West Virginia, the FBI said in a statement.
His odyssey has spanned more than 600 miles north, from Charleston, South Carolina, to Louisville, Kentucky, and about 500 miles east, from Knoxville, Tennessee, to Edenton, North Carolina.
The robberies started in May and the most recent one was last week in Tennessee, Keithley said.
The suspect is described as white, about 25 years old, 5 feet 9 to 5 feet 11, 170 to 175 pounds. He has short, reddish-brown hair and an unshaven goatee, the FBI said.
The suspect has not yet harmed anybody in the robberies but the FBI considers him extremely dangerous.
"This guy has made no effort to hide the gun," Keithley said. "He has threatened the use of it in every bank robbery he has committed. He has put the gun in the faces of tellers, threatened to use the gun against them. So we want to get this guy in custody before he harms anyone."
In surveillance video of a robbery in Fletcher, North Carolina, the suspect is seen talking into a handheld radio, said an FBI official involved in the investigation. In a South Carolina robbery, a wireless phone device is seen on his ear.
"That prompted us to look at the prospect of another suspect out there helping him, and we continue to look for that angle but have no leads into that as of now," the FBI official said.
Authorities are also working with police agencies, corrections departments and others who use facial recognition technology, the official said, and are working with corrections departments on tattoo identifications, recorded by prisons in some states.
Since the national billboard program began in 2008, the billboards have been directly responsible for the apprehension of at least 20 fugitives, said Stephen Emmett, spokesman for the FBI's Atlanta office.
"We try to reserve the billboards for the more mobile, more egregious, violent offenders, because we understand we're pulling resources away from a corporate entity, and we try not to take advantage of that," he said. "But they are a very valuable tool to law enforcement in these type of cases where the individual is highly mobile and very dangerous."
The bank robbery suspect has distinctive tattoos on his forearms, Emmett noted. "Somebody will recognize these tattoos. Somebody will recognize this individual. The remarkable thing about this serial bank robber is that he did not attempt whatsoever to disguise himself. The photographs from these cases are very good, very detailed. The public will know who this individual is."
He said his past experience, as well as statistics, show that "there are addiction issues with the majority of these bank robbers, and that provides a bad additional ingredient to this bank robbery scenario. You have an individual going into a bank with a gun, in a reckless manner, and now he might actually be on drugs and strung out on drugs. So that makes this even more imperative, to get this individual off the street before anybody gets hurt and to get him the help that he needs."
Robbing banks is not as lucrative as the public might believe, he said, and "with addiction-type motives by these robbers, they tend to get only enough money to get their next fix." It's possible the suspect's family members may not know of his activities, Emmett said.
"He's an individual that we want off of the street in the worst way," he said, "and we feel these billboards are a tool. We feel the photographs from the banks are going to make that happen."
The FBI asks anybody who knows the bank robber or who has information in the case to call 423-282-8090. A reward is being offered.
CNN's John Murgatroyd contributed to this report.