PHOENIX -- The FBI bank robbery task force said it needs the public's help in identifying the so-called "Slingblade Bandits" who have robbed a Valley credit union and a bank.

The most recent robbery occurred on Tuesday at a Wells Fargo Bank at 1901 S. Gilbert Road in Mesa.

A man approached the teller and displayed a handgun which was concealed inside a sling on his left arm, the FBI said. He verbally demanded money and handed over a demand note but the teller did not read it, FBI agents said. The man received an undisclosed amount of money and left the bank on foot.

The man is described as in his 30s and between 5 feet 6 inches to 5 feet 8 inches tall. He was last seen wearing a black baseball cap, black sunglasses, white bandages on right side of his face and a light green, drab-colored long-sleeved shirt with the word "Military" on the front. He also wore dark pants, had an arm sling on his left arm and was carrying a black semi-auto handgun.

On June 29, the FBI said a man entered the Arizona Federal Credit Union at 1311 W. Chandler Boulevard in Chandler. He approached the teller window and handed the teller a demand note, FBI agents said.

The robber then opened a sling on his left arm and displayed a semi-auto handgun, the FBI said. The man was given an undisclosed amount of money and he left the bank on foot.

He is described as being in his 40s. He is 5 feet 8 inches tall and weighs 280 pounds. The man has a mustache and goatee and was last seen wearing a grey T-shirt, dark baseball cap and prescription eyeglasses. he wore a dark arm sling on left arm that concealing a semi-auto handgun, the FBI said.

People with any information about the robberies should contact the FBI Phoenix Division at 602-279-5511.