The witness, identified as P-031, was testifying in the trial of Mile Mrksic, Miroslav Radic and Veselin Sljivancanin, who are charged with crimes against humanity and violations of the laws and customs of war committed through the execution of at least 264 POWs from the Vukovar Hospital at the Ovcara farm outside the town.
The witness, who after the fall of the town on 18 November took shelter in the hospital with hundreds of other civilians, described in detail the events that took place in the hospital on 19 and 20 November and how men were separated from women and taken to the JNA barracks and later to Ovcara, where they were killed.
The witness said that the separation of men from women was overseen by Sljivancanin, whom he described as arrogant.
The prisoners were taken by bus to the JNA barracks, where they were subjected to intimidation and abuse by Serb paramilitaries.
The prisoners were then taken to Ovcara, taken out of the buses one by one, with JNA members confiscating their personal belongings, money, jewellery and other valuables.
They then had to run the gauntlet, with members of Serb paramilitary units kicking them and beating them with wooden bats and crutches.
The witness described how the prisoners were led into a hangar and lined up facing the wall, with their hands behind their heads.
Young soldiers were standing in the middle of the hangar, inspecting the prisoners, coming up to them and taunting and threatening them and demanding money, the witness said.
He added that he was recognised by a Serb soldier, a friend of his son, who took him out of the hangar. The soldier explained to the guard standing at the entrance to the hangar that he knew the prisoner and that he was not guilty of anything, so the guard let them out.
P-031 was then taken with five other POWs back to Vukovar, to a local company building. They were put in a room which the prisoners referred to as "The Death Room".
The witness said that three POWs were taken out of the room and that they never returned.
On the evening of 21 November a JNA captain transferred the remaining POWs to the JNA barracks "so they all would not be killed". The following morning the witness was taken by bus with 37 other prisoners to a detention camp in Sremska Mitrovica in Serbia, where he stayed until he was exchanged.
The witness is due to be cross-examined by defence counsel on Thursday.