The latest incident occurred Tuesday at approximately 9:55 a.m. at the Heartland Community Credit Union in Mason City, Iowa, according to a news release from FBI spokeswoman Laura Eimiller.
The nickname refers to the type of assault rifle the man has brandished while targeting banks in five states.
In Tuesday’s heist, the bandit was also armed with an AK-47 with a high-capacity drum magazine, Eimiller stated.
He stole an undisclosed amount of money and drove away in a 2007 to 2009 black or dark-colored Toyota Camry LE, according to the FBI.
The bandit was described as a white man, between 20 and 40 years old, standing 5 foot 9 inches to 6 feet tall, with a medium build.
He was wearing a black ski mask and gloves.
The robber left behind a suspicious item that was rendered safe by FBI bomb squad personnel, according to Eimiller.
A reward of up to $100,000 was being offered in exchange for information leading to the arrest and conviction of the robber.
Anyone with information is asked to call their nearest FBI office or the Chino Police Department at 909-628-1234.