This case, researched by Hans Bender, involved the production of significant rapping sounds in the vicinity of two sisters, aged 11 and 13. The phenomena usually occurred when they were lying in bed together. 

 The effects were observed at close quarters and Bender was convinced that the rappings were paranormal in origin. Many recordings were made of the phenomena themselves as well as the verbal exchanges which took place between the sisters. This file was available as 16-bit stereo and 44100Hz. It lasted for about 38 seconds and had an uncompressed size of 6.4MB.