Although it seemed like the work of a prankster, officers uncovered a much smaller culprit: ants.

 

Police in Offenburg responded when the 75-year-old woman made a desperate call at 3 a.m. on Wednesday, the German news magazine Focus reported. But when they arrived, officers didn’t find anyone at the door. On closer inspection they found that ants had built such a large nest that it was pressing the doorbell components together to make it ring.

 

Although the brief news report didn’t identify the type of ant that caused the disturbance, the Guardian’s Patrick Barkham floated a couple of theories.