A US IT worker fed up at having his food taken has taken steps to stop it ever happening again.
The man, known by YouTube username mallusdei, noticed the food disappearing from his desk over a one-month period so he placed a webcam above his computer overnight and left it recording.
The video showed a female janitor walk to his desk and take a piece of fruit, which she began eating without hesitation.
The IT worker then posted a message on his screensaver saying "I know who you are. Stop stealing my things, or I will report you" along with images of the woman caught in the act and set the webcam to record again.
In the second part of the video one of the janitor's colleagues notices the screensaver and shows her.
The culprit stares at the screen with her mouth open and eyes wide.
Mallusdei uploaded the video to YouTube on June 29, where it has been viewed thousands of times.