After a decade of finding holes brimming with human excrement, Stavanger Golf Club in Norway has gone public with its quest to unmask the culprit.

The course enacted new security measures and installed flood lighting to no avail, according to groundskeeper Kenneth Tennfjord. He believes the mystery dumper is likely male because the stools are "massive."

Stavanger Golf Club, a waterside course in Hafrsfjord, first noted the problem in 2005. Tennfjord says that the placements favor particular holes, occur late at night and up to several times a week, and that the person doing so leaves used toilet paper behind as well.

"The early years were relatively hard stools, but the consistency has changed," Tennfjord told local reporters [translate].

The culprit even "climbed high up a tree … wriggled out on a branch and dismantled spotlights," Tennfjord added. "How he managed this feat without falling is a riddle."