When you want something, just ask. Apparently that is the adage that applied to a bank robber in Chicago.

Police say the robber sent a note through a vacuum tube to the teller at the drive-through window at a branch of Chicago's LaSalle Bank and the teller obliged, returning an undisclosed amount of cash.

The exchange was completed through the bank's pneumatic tube communications system, in which canisters are passed back and forth between motorist and teller.

The FBI says it was investigating the drive-through theft.