The Douglas County Courthouse, 1100 Mass., was evacuated about noon today after an employee thought she smelled a “slight amount” of gas in the attic.

It turned out that the smell was actually coming from a dead mouse, County Administrator Craig Weinaug said.

“It’s one of those things where the outcome was humorous but everybody did what they were supposed to do,” Weinaug said.

An employee from the Register of Deeds office was in the attic looking for records when she detected the smell, Weinaug said. The fire department and sheriff’s office was called and the decision was made to evacuate the building, he said.

“You laugh after it’s over but when it happens you just go into an automatic mode and do what needs to be done,” Weinaug said. “I don’t know if the mouse has actually been moved to a safer resting place.”