Two years after first being reported as lost, 21 artworks are still missing from Leinster House, which houses Ireland’s parliament in Dublin, the Sunday Independent reports.

The Office of Public Works and the Houses of the Oireachtas gave a statement last weekend explaining that the inventory process to account for the lost artworks is still “ongoing,” and that an official investigation is well underway. Works by Brett McEntaggart and Robert Ballagh are among those missing.

Several possible explanations for the works’ disappearance are currently being explored. There are concerns that some works might have been stolen, but sources from Leinster House have suggested that a number pieces might have been moved and misplaced during the changeover that ensued after the 2011 general elections.

The full collection, displayed across the 11 buildings that constitute Leinster House, is comprised of 720 artworks, both contemporary and historical, including works by Irish artists like Leo Whelan, Sean O’Sullivan, Maurice McGonigal, Patrick Hickey, Tom Ryan, James Hanley, Mary Fitzgerald, and Cora Cummins. Of these, 290 are paintings, 365 are prints, and 24 are sculptures. Twenty-one drawings, 14 photographs, and four textile pieces complete the art collection.

The Sunday Independent initially reported on the disappearance of the artworks in October 2012, claiming that 37 pieces had gone AWOL. The figure has been lowered since to the current 21 artworks, still unaccounted for.