A professor at Umea University in northern Sweden had his laptop stolen but was completely surprised when the thief mailed him back the computer's contents on a memory stick.

"This story makes me feel hope for humanity," the professor, who wished to remain anonymous, told local paper Vasterbottens-Kuriren.

The professor left his bag in the stairwell of his apartment complex while he went to the laundry room. When he came back the bag and all of its contents — including his wallet, datebook and laptop were gone.

After reporting the theft to police, the professor returned to his apartment to find his bag and its contents — except for the laptop — back at the stairwell.

A week later he received an envelope in the mail containing a USB memory stick that had all the files and documents from his laptop, which would have taken the culprit hours to copy and paste.

The laptop, as well as the professor's library card, has yet to be returned.

"Perhaps the thief needs to improve him or herself," he told the paper.