▁rule ▁in ▁Poland ▁( which ▁last ed ▁until ▁ 1 9 8 9 ), ▁fact ual ▁knowledge ▁of ▁these ▁events ▁was ▁cens ored ▁by ▁the ▁commun ist ▁government , ▁and ▁the ▁mass ▁grave ▁was ▁kept ▁anonymous . ▁It ▁was ▁not ▁until ▁the ▁ 6 0 th ▁anni versary ▁of ▁the ▁event ▁in ▁ 2 0 0 5 ▁that ▁a ▁mem orial ▁stone ▁was ▁ere cted ▁at ▁the ▁c emetery . ▁The ▁comm emor ative ▁ceremony ▁was ▁performed ▁by ▁the ▁bishop ▁of ▁Leg nica , ▁Stefan ▁C ich y , ▁who ▁was ▁personally ▁an ▁eye - w it ness ▁to ▁the ▁events , ▁as ▁well ▁as ▁a ▁relative ▁of ▁one ▁of ▁the ▁vict ims . ▁ ▁Ar ound ▁that ▁time , ▁the ▁Kat ow ice ▁branch ▁of ▁the ▁Institute ▁of ▁National ▁Rem emb rance ▁( IP N ) ▁started ▁an ▁investigation ▁into ▁the ▁events , ▁as ▁well ▁as ▁on ▁similar ▁mass ac res ▁carried ▁out ▁in ▁Gli w ice ▁and ▁R uda ▁Ś lą ska - H alem ba . ▁During ▁the ▁investigation , ▁various ▁documents ▁provided ▁by ▁the ▁Def ence ▁Ministry ▁of ▁the ▁Russian ▁Federation ▁were ▁exam ined , ▁however , ▁there ▁was ▁ins u fficient ▁information ▁to ▁determine ▁which ▁units ▁of ▁the ▁Red ▁Army ▁participated ▁in ▁the ▁mass acre ▁or ▁who ▁was ▁responsible ▁for ▁the ▁kill ings . ▁In ▁reporting ▁the ▁results ▁of ▁its ▁investigation , ▁the ▁IP N ▁declared ▁the ▁ 1 9 4 5 ▁events ▁in ▁Prz ysz ow ice ▁a ▁crime ▁against ▁human ity . ▁It ▁is ▁estimated ▁that