OKLAHOMA CITY (AP) - The FBI is seeking information about six unsolved bank robberies in the Tulsa area.

Officials say the heists happened between May 2011 and March.

The most violent robbery occurred Sept. 16 at the Tulsa Municipal Employees Federal Credit Union. Three males pointed firearms at the customers and employees.

One of the robbers shot through the glass where a teller was standing and jumped over the counter. They took cash before fleeing in a Jeep Cherokee.

All were described as black males in their 20s.

In a May 28, 2011 IBC Bank robbery in Bixby, authorities say a white male pointed a gun at the teller, demanded money and fled. He was 25 to 35 years old and weighed about 150 pounds.

Officials say he was seen driving a tan vehicle.