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(CNN) -- A tip led to Wednesday's arrest in Louisiana of a suspected serial bank robber dubbed the "Granddad Bandit," federal authorities said.
Michael Francis Mara, 52, was captured at his home in Baton Rouge, FBI Special Agent Sheila Thorne told CNN.
The FBI went to the residence to execute an arrest warrant when Mara retreated into the house, she said. "After six hours, he came out and was placed under arrest," she added.
The "Granddad Bandit" is wanted in at least 25 bank heists in 13 states -- from Virginia to Texas to Kansas -- since 2008, the FBI said in a statement. He was given the name because he appeared elderly, Thorne told CNN.
The bandit, described as balding, heavy and wearing glasses, captured the public's attention because of his non-threatening image and his nickname.
But federal authorities said he was anything but harmless. He would point to his waistband and indicate he had a gun, but it was unclear if he actually had one.
The Federal Bureau of Investigation's field office in Norfolk, Virginia, got a tip earlier this month, the U.S. Attorney's Office for the Eastern District of Virginia said Wednesday.
The tipster identified and provided photographs of Mara that were compared to surveillance footage, the office said in a statement. Investigators "allegedly found consistent key identifiers between the surveillance images and the photographs of Mara, including a hat, eyeglasses and wrist watch that appear to be identical."
Mara has been charged with one count of bank robbery and is in custody, Thorne said. He could receive a 20-year sentence if convicted.
Mara worked for a vehicle transportation company and traveled from state to state on business, the FBI said.
In recent weeks, the FBI launched a billboard campaign featuring surveillance pictures of the robber hoping he would be identified. Authorities cited this and other publicity as being effective.
An FBI affidavit released Wednesday gave some insight into how the "Granddad Bandit" did his business.
"[He] presents a demand note with a request for the specific dollar amount. The Subject does not appear to wear any disguises or concealment to hide his identity. The subject enters the bank calmly, oftentimes patiently waiting for his turn in line and then approaches the victim teller," the affidavit said.
"Once the Subject's demands are met, he retrieves the demand note and exits the bank quietly, not bringing attention to the crime he just committed."
CNN's Gabriel Falcon and Carol Cratty contributed to this article.