Police did not disclose how much money the case contained.
"Obviously, it's enough that we want it back," Small said.
According to Small, the container is gray with a blue handle. It is about 18 inches long, 9 inches wide and 5 inches deep.
Small said the container might have been taken by a passer-by or simply be missing.
"Who knows?" he said. "You could speculate all sorts of things."
Small added that it is a crime to take money even if it is lying on the ground.
"By law, finding money that isn't yours and making it your own is actually theft," he said. "So if someone has it, that would be theft."
Dave Barnhart, vice president for marketing at Hagerstown Trust, commended the customer's honesty.
"We were grateful to the patron for bringing the money in," he said.
As for the missing canister, Barnhart said it is exclusively a matter for Diebold Inc. and Executive Cash Services, its subcontractor.
"The responsibility and liability is squarely on Diebold and their subcontractor," he said.
Officials from Diebold's Frederick branch were unavailable for comment Friday afternoon.
Executive Cash Services' Operations Manager Mark Decker, reached at the firm's Hammonton, N.J. offices, declined comment.
The incident stirs memories of a similar missing-money episode seven years ago. In 1989, armored car personnel reported missing a bag containing $5,000. The money apparently had fallen off a cart at the Valley Mall when several bags were being loaded into the car.
A Morgan County, W.Va., couple that found the money received a $5,000 reward for handing the bag over to police.
The owner and four maids at the Ramada Inn each received a $5,000 reward for turning over $422,383 they found in 1983 in another instance of missing money. That cash was believed to be left behind by a drug smuggler.
In 1993, a Washington County resident returned a large sum of money found in the Huyetts Crossroads area.
Small said any assistance finding the lost money container will be greatly appreciated.