Further investigations were then performed in 1900 by Alessandro Barsanti,[3] who uncovered the vertical access shaft leading to the burial chamber. Barsanti, seeing that several corridors and chambers were seemingly unfinished and that all were completely devoid of artefacts, deemed that the pyramid had never been used.[3] Shortly after, in 1910–1911, George Reisner and Clarence S. Fisher worked on the site,[6] excavating the north and east exteriors of the pyramid as well as the cemeteries surrounding it.[3][4][5][7] The dimensions of the pyramid as estimated by Barsanti, Reisner and Fisher differ greatly and even the numbers of subterranean galleries they report are in disagreement.[8] Unfortunately, the pyramid lies within a restricted military area since 1970 and consequently no excavation has been undertaken there since Reisner and Fisher's superficial work,[4][5] leaving the structures beneath the pyramid in doubt.