Jim Graceffa and Bud Henderson had come out to the Sugarloaf ruin a week ago Monday to survey some fence lines.
Founding members of the Verde Valley Archaeology Center, they had been invited by the property owners, the Archaeology Conservancy, as part of a management agreement between the two organizations.
But while walking the property searching for property markers, they were told by a neighbor that some pot hunting materials had been found at the at the hilltop site.
Hata'lacva, near Clarkdale, was professionally excavated in 1933 and 1934 as part of the Tuzigoot excavation and restoration and like Sugarloaf is owned by the Archaeology Conservancy.
Pilles says the recent rash of rock art defacing is of concern to researchers and frustrating to those whose job it is to protect them.