Witnesses before ICTY stated that on the early morning of 22 May 1999 the prisoners were told to line up on the sports field, with the explanation that they were to be transferred to other more secure prisons. About 800 prisoners obeyed while the rest hid themselves in the jail. After the prisoners formed a line, police started firing from the guard tower and the jail walls, using hand grenades, bazookas and automatic weapons.[1] The witnesses said about 20 officers opened fire.